On Sat, 23 Dec 2023 at 09:29, Simon Horman <[email protected]> wrote:
>
>
> if (data[0] == 0) {
> /* It may be a server list. */
> - if (datalen <= sizeof(*bin))
> + if (datalen <= sizeof(*v1))
> return -EINVAL;
>
> bin = (const struct dns_payload_header *)data;
Ugh, I hate how it checks the size of a *different* structure than the
one it then assigns the pointer to.
So I get the feeling that we should get rid of 'bin' entirely, and
just use the 'v1' pointer, since it literally checks that that is what
it is, and then the size check matches the thing we're casting things
to.
So then "bin->xyz" becomes "v1->hdr.xyz".
Yes, the patch becomes a bit bigger, but I think the end result is a
whole lot more obvious and maintainable.
I'd also move the remaining 'v1' variable declaration to the inner
context where it's actually used.
IOW, I personally would be much happier with a patch like the attached, but I
(a) don't want to take credit for this, since my change is purely syntactic
(b) have not tested this patch apart from checking that it compiles
in at least one config
so honestly, I'd love to see this patch come back to me with sign-offs
and tested-bys by the actual people who noticed this.
Hmm?
Linus
Hi Linus, Edward,
Here's Linus's patch dressed up with a commit message. I would marginally
prefer just to insert the missing size check, but I'm also fine with Linus's
approach for now until we have different content types or newer versions.
Note that I'm not sure whether I should require Linus's S-o-b since he made
modifications or whether I should use a Codeveloped-by line for him.
David
---
From: Edward Adam Davis <[email protected]>
keys, dns: Fix missing size check of V1 server-list header
The dns_resolver_preparse() function has a check on the size of the payload
for the basic header of the binary-style payload, but is missing a check
for the size of the V1 server-list payload header after determining that's
what we've been given.
Fix this by getting rid of the the pointer to the basic header and just
assuming that we have a V1 server-list payload and moving the V1 server
list pointer inside the if-statement. Dealing with other types and
versions can be left for when such have been defined.
This can be tested by doing the following with KASAN enabled:
echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
and produces an oops like the following:
BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
...
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:377 [inline]
print_report+0xc3/0x620 mm/kasan/report.c:488
kasan_report+0xd9/0x110 mm/kasan/report.c:601
dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
__key_create_or_update+0x453/0xdf0 security/keys/key.c:842
key_create_or_update+0x42/0x50 security/keys/key.c:1007
__do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x62/0x6a
This patch was originally by Edward Adam Davis, but was modified by Linus.
Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
Reported-and-tested-by: [email protected]
Link: https://lore.kernel.org/r/[email protected]/
Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Edward Adam Davis <[email protected]>
Signed-off-by: David Howells <[email protected]>
Tested-by: David Howells <[email protected]>
cc: Edward Adam Davis <[email protected]>
cc: Simon Horman <[email protected]>
cc: Linus Torvalds <[email protected]>
cc: Jarkko Sakkinen <[email protected]>
cc: Jeffrey E Altman <[email protected]>
cc: Wang Lei <[email protected]>
cc: Jeff Layton <[email protected]>
cc: Steve French <[email protected]>
cc: Marc Dionne <[email protected]>
cc: "David S. Miller" <[email protected]>
cc: Eric Dumazet <[email protected]>
cc: Jakub Kicinski <[email protected]>
cc: Paolo Abeni <[email protected]>
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
cc: [email protected]
---
net/dns_resolver/dns_key.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index 2a6d363763a2..f18ca02aa95a 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
static int
dns_resolver_preparse(struct key_preparsed_payload *prep)
{
- const struct dns_server_list_v1_header *v1;
- const struct dns_payload_header *bin;
struct user_key_payload *upayload;
unsigned long derrno;
int ret;
@@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
return -EINVAL;
if (data[0] == 0) {
+ const struct dns_server_list_v1_header *v1;
+
/* It may be a server list. */
- if (datalen <= sizeof(*bin))
+ if (datalen <= sizeof(*v1))
return -EINVAL;
- bin = (const struct dns_payload_header *)data;
- kenter("[%u,%u],%u", bin->content, bin->version, datalen);
- if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
+ v1 = (const struct dns_server_list_v1_header *)data;
+ kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
+ if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
pr_warn_ratelimited(
"dns_resolver: Unsupported content type (%u)\n",
- bin->content);
+ v1->hdr.content);
return -EINVAL;
}
- if (bin->version != 1) {
+ if (v1->hdr.version != 1) {
pr_warn_ratelimited(
"dns_resolver: Unsupported server list version (%u)\n",
- bin->version);
+ v1->hdr.version);
return -EINVAL;
}
- v1 = (const struct dns_server_list_v1_header *)bin;
if ((v1->status != DNS_LOOKUP_GOOD &&
v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
if (prep->expiry == TIME64_MAX)
On Sun, Dec 24, 2023 at 12:02:49AM +0000, David Howells wrote:
> Hi Linus, Edward,
>
> Here's Linus's patch dressed up with a commit message. I would marginally
> prefer just to insert the missing size check, but I'm also fine with Linus's
> approach for now until we have different content types or newer versions.
>
> Note that I'm not sure whether I should require Linus's S-o-b since he made
> modifications or whether I should use a Codeveloped-by line for him.
>
> David
> ---
> From: Edward Adam Davis <[email protected]>
>
> keys, dns: Fix missing size check of V1 server-list header
>
> The dns_resolver_preparse() function has a check on the size of the payload
> for the basic header of the binary-style payload, but is missing a check
> for the size of the V1 server-list payload header after determining that's
> what we've been given.
>
> Fix this by getting rid of the the pointer to the basic header and just
> assuming that we have a V1 server-list payload and moving the V1 server
> list pointer inside the if-statement. Dealing with other types and
> versions can be left for when such have been defined.
>
> This can be tested by doing the following with KASAN enabled:
>
> echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
>
> and produces an oops like the following:
>
> BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
> ...
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:377 [inline]
> print_report+0xc3/0x620 mm/kasan/report.c:488
> kasan_report+0xd9/0x110 mm/kasan/report.c:601
> dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> __key_create_or_update+0x453/0xdf0 security/keys/key.c:842
> key_create_or_update+0x42/0x50 security/keys/key.c:1007
> __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x62/0x6a
>
> This patch was originally by Edward Adam Davis, but was modified by Linus.
>
> Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> Reported-and-tested-by: [email protected]
> Link: https://lore.kernel.org/r/[email protected]/
> Suggested-by: Linus Torvalds <[email protected]>
> Signed-off-by: Edward Adam Davis <[email protected]>
> Signed-off-by: David Howells <[email protected]>
> Tested-by: David Howells <[email protected]>
Thanks.
FWIIW, I prefer this approach where v1 and bin don't alias each other,
and the scope of v1 is constrained to the block where it is used.
Reviewed-by: Simon Horman <[email protected]>
...
On 2023-12-24 at 00:02:49 +0000, David Howells wrote:
> Hi Linus, Edward,
>
> Here's Linus's patch dressed up with a commit message. I would marginally
> prefer just to insert the missing size check, but I'm also fine with Linus's
> approach for now until we have different content types or newer versions.
>
> Note that I'm not sure whether I should require Linus's S-o-b since he made
> modifications or whether I should use a Codeveloped-by line for him.
>
> David
> ---
> From: Edward Adam Davis <[email protected]>
>
> keys, dns: Fix missing size check of V1 server-list header
>
> The dns_resolver_preparse() function has a check on the size of the payload
> for the basic header of the binary-style payload, but is missing a check
> for the size of the V1 server-list payload header after determining that's
> what we've been given.
>
> Fix this by getting rid of the the pointer to the basic header and just
> assuming that we have a V1 server-list payload and moving the V1 server
> list pointer inside the if-statement. Dealing with other types and
> versions can be left for when such have been defined.
>
> This can be tested by doing the following with KASAN enabled:
>
> echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
>
> and produces an oops like the following:
>
> BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
> ...
> Call Trace:
> <TASK>
> __dump_stack lib/dump_stack.c:88 [inline]
> dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> print_address_description mm/kasan/report.c:377 [inline]
> print_report+0xc3/0x620 mm/kasan/report.c:488
> kasan_report+0xd9/0x110 mm/kasan/report.c:601
> dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> __key_create_or_update+0x453/0xdf0 security/keys/key.c:842
> key_create_or_update+0x42/0x50 security/keys/key.c:1007
> __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
> do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> entry_SYSCALL_64_after_hwframe+0x62/0x6a
>
> This patch was originally by Edward Adam Davis, but was modified by Linus.
>
> Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> Reported-and-tested-by: [email protected]
> Link: https://lore.kernel.org/r/[email protected]/
> Suggested-by: Linus Torvalds <[email protected]>
> Signed-off-by: Edward Adam Davis <[email protected]>
> Signed-off-by: David Howells <[email protected]>
> Tested-by: David Howells <[email protected]>
> cc: Edward Adam Davis <[email protected]>
> cc: Simon Horman <[email protected]>
> cc: Linus Torvalds <[email protected]>
> cc: Jarkko Sakkinen <[email protected]>
> cc: Jeffrey E Altman <[email protected]>
> cc: Wang Lei <[email protected]>
> cc: Jeff Layton <[email protected]>
> cc: Steve French <[email protected]>
> cc: Marc Dionne <[email protected]>
> cc: "David S. Miller" <[email protected]>
> cc: Eric Dumazet <[email protected]>
> cc: Jakub Kicinski <[email protected]>
> cc: Paolo Abeni <[email protected]>
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> cc: [email protected]
> ---
> net/dns_resolver/dns_key.c | 19 +++++++++----------
> 1 file changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
> index 2a6d363763a2..f18ca02aa95a 100644
> --- a/net/dns_resolver/dns_key.c
> +++ b/net/dns_resolver/dns_key.c
> @@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
> static int
> dns_resolver_preparse(struct key_preparsed_payload *prep)
> {
> - const struct dns_server_list_v1_header *v1;
> - const struct dns_payload_header *bin;
> struct user_key_payload *upayload;
> unsigned long derrno;
> int ret;
> @@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
> return -EINVAL;
>
> if (data[0] == 0) {
> + const struct dns_server_list_v1_header *v1;
> +
> /* It may be a server list. */
> - if (datalen <= sizeof(*bin))
> + if (datalen <= sizeof(*v1))
> return -EINVAL;
>
> - bin = (const struct dns_payload_header *)data;
> - kenter("[%u,%u],%u", bin->content, bin->version, datalen);
> - if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
> + v1 = (const struct dns_server_list_v1_header *)data;
> + kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
> + if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
> pr_warn_ratelimited(
> "dns_resolver: Unsupported content type (%u)\n",
> - bin->content);
> + v1->hdr.content);
> return -EINVAL;
> }
>
> - if (bin->version != 1) {
> + if (v1->hdr.version != 1) {
> pr_warn_ratelimited(
> "dns_resolver: Unsupported server list version (%u)\n",
> - bin->version);
> + v1->hdr.version);
> return -EINVAL;
> }
>
> - v1 = (const struct dns_server_list_v1_header *)bin;
> if ((v1->status != DNS_LOOKUP_GOOD &&
> v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
> if (prep->expiry == TIME64_MAX)
>
Hi Edward and kernel experts,
Above patch(upstream commit: 1997b3cb4217b09) seems causing a keyctl05 case
to fail in LTP:
https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/keyctl/keyctl05.c
It could be reproduced on a bare metal platform.
Kconfig: https://raw.githubusercontent.com/xupengfe/kconfig_diff/main/config_v6.7-rc8
Seems general kconfig could reproduce this issue.
Bisected info between v6.7-rc7(keyctl05 passed) and v6.7-rc8(keyctl05 failed)
is in attached.
keyctl05 failed in add_key with type "dns_resolver" syscall step tracked
by strace:
"
[pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
[pid 863106] <... alarm resumed>) = 30
[pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
"
Passed behavior in v6.7-rc7 kernel:
"
[pid 6726] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
[pid 6725] rt_sigreturn({mask=[]}) = 61
[pid 6726] <... add_key resumed>) = 1029222644
"
Do you mind to take a look for above issue?
Best Regards,
Thanks!
On Wed, 10 Jan 2024 12:40:41 +0800, Pengfei Xu wrote:
> > Hi Linus, Edward,
> >
> > Here's Linus's patch dressed up with a commit message. I would marginally
> > prefer just to insert the missing size check, but I'm also fine with Linus's
> > approach for now until we have different content types or newer versions.
> >
> > Note that I'm not sure whether I should require Linus's S-o-b since he made
> > modifications or whether I should use a Codeveloped-by line for him.
> >
> > David
> > ---
> > From: Edward Adam Davis <[email protected]>
> >
> > keys, dns: Fix missing size check of V1 server-list header
> >
> > The dns_resolver_preparse() function has a check on the size of the payload
> > for the basic header of the binary-style payload, but is missing a check
> > for the size of the V1 server-list payload header after determining that's
> > what we've been given.
> >
> > Fix this by getting rid of the the pointer to the basic header and just
> > assuming that we have a V1 server-list payload and moving the V1 server
> > list pointer inside the if-statement. Dealing with other types and
> > versions can be left for when such have been defined.
> >
> > This can be tested by doing the following with KASAN enabled:
> >
> > echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
> >
> > and produces an oops like the following:
> >
> > BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
> > ...
> > Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> > print_address_description mm/kasan/report.c:377 [inline]
> > print_report+0xc3/0x620 mm/kasan/report.c:488
> > kasan_report+0xd9/0x110 mm/kasan/report.c:601
> > dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > __key_create_or_update+0x453/0xdf0 security/keys/key.c:842
> > key_create_or_update+0x42/0x50 security/keys/key.c:1007
> > __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
> > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > entry_SYSCALL_64_after_hwframe+0x62/0x6a
> >
> > This patch was originally by Edward Adam Davis, but was modified by Linus.
> >
> > Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> > Reported-and-tested-by: [email protected]
> > Link: https://lore.kernel.org/r/[email protected]/
> > Suggested-by: Linus Torvalds <[email protected]>
> > Signed-off-by: Edward Adam Davis <[email protected]>
> > Signed-off-by: David Howells <[email protected]>
> > Tested-by: David Howells <[email protected]>
> > cc: Edward Adam Davis <[email protected]>
> > cc: Simon Horman <[email protected]>
> > cc: Linus Torvalds <[email protected]>
> > cc: Jarkko Sakkinen <[email protected]>
> > cc: Jeffrey E Altman <[email protected]>
> > cc: Wang Lei <[email protected]>
> > cc: Jeff Layton <[email protected]>
> > cc: Steve French <[email protected]>
> > cc: Marc Dionne <[email protected]>
> > cc: "David S. Miller" <[email protected]>
> > cc: Eric Dumazet <[email protected]>
> > cc: Jakub Kicinski <[email protected]>
> > cc: Paolo Abeni <[email protected]>
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > ---
> > net/dns_resolver/dns_key.c | 19 +++++++++----------
> > 1 file changed, 9 insertions(+), 10 deletions(-)
> >
> > diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
> > index 2a6d363763a2..f18ca02aa95a 100644
> > --- a/net/dns_resolver/dns_key.c
> > +++ b/net/dns_resolver/dns_key.c
> > @@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
> > static int
> > dns_resolver_preparse(struct key_preparsed_payload *prep)
> > {
> > - const struct dns_server_list_v1_header *v1;
> > - const struct dns_payload_header *bin;
> > struct user_key_payload *upayload;
> > unsigned long derrno;
> > int ret;
> > @@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
> > return -EINVAL;
> >
> > if (data[0] == 0) {
> > + const struct dns_server_list_v1_header *v1;
> > +
> > /* It may be a server list. */
> > - if (datalen <= sizeof(*bin))
> > + if (datalen <= sizeof(*v1))
> > return -EINVAL;
> >
> > - bin = (const struct dns_payload_header *)data;
> > - kenter("[%u,%u],%u", bin->content, bin->version, datalen);
> > - if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > + v1 = (const struct dns_server_list_v1_header *)data;
> > + kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
> > + if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > pr_warn_ratelimited(
> > "dns_resolver: Unsupported content type (%u)\n",
> > - bin->content);
> > + v1->hdr.content);
> > return -EINVAL;
> > }
> >
> > - if (bin->version != 1) {
> > + if (v1->hdr.version != 1) {
> > pr_warn_ratelimited(
> > "dns_resolver: Unsupported server list version (%u)\n",
> > - bin->version);
> > + v1->hdr.version);
> > return -EINVAL;
> > }
> >
> > - v1 = (const struct dns_server_list_v1_header *)bin;
> > if ((v1->status != DNS_LOOKUP_GOOD &&
> > v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
> > if (prep->expiry == TIME64_MAX)
> >
>
> Hi Edward and kernel experts,
>
> Above patch(upstream commit: 1997b3cb4217b09) seems causing a keyctl05 case
> to fail in LTP:
> https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/keyctl/keyctl05.c
>
> It could be reproduced on a bare metal platform.
> Kconfig: https://raw.githubusercontent.com/xupengfe/kconfig_diff/main/config_v6.7-rc8
> Seems general kconfig could reproduce this issue.
>
> Bisected info between v6.7-rc7(keyctl05 passed) and v6.7-rc8(keyctl05 failed)
> is in attached.
>
> keyctl05 failed in add_key with type "dns_resolver" syscall step tracked
> by strace:
> "
> [pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> [pid 863106] <... alarm resumed>) = 30
> [pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
The reason for the failure of add_key() is that the length of the incoming data
is 5, which is less than sizeof(*v1), so keyctl05.c failed.
Suggest modifying keyctl05.c to increase the length of the incoming data to 6
bytes or more.
> "
>
> Passed behavior in v6.7-rc7 kernel:
> "
> [pid 6726] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> [pid 6725] rt_sigreturn({mask=[]}) = 61
> [pid 6726] <... add_key resumed>) = 1029222644
> "
>
> Do you mind to take a look for above issue?
Edward,
BR
On 2024-01-10 at 12:40:41 +0800, Pengfei Xu wrote:
> On 2023-12-24 at 00:02:49 +0000, David Howells wrote:
> > Hi Linus, Edward,
> >
> > Here's Linus's patch dressed up with a commit message. I would marginally
> > prefer just to insert the missing size check, but I'm also fine with Linus's
> > approach for now until we have different content types or newer versions.
> >
> > Note that I'm not sure whether I should require Linus's S-o-b since he made
> > modifications or whether I should use a Codeveloped-by line for him.
> >
> > David
> > ---
> > From: Edward Adam Davis <[email protected]>
> >
> > keys, dns: Fix missing size check of V1 server-list header
> >
> > The dns_resolver_preparse() function has a check on the size of the payload
> > for the basic header of the binary-style payload, but is missing a check
> > for the size of the V1 server-list payload header after determining that's
> > what we've been given.
> >
> > Fix this by getting rid of the the pointer to the basic header and just
> > assuming that we have a V1 server-list payload and moving the V1 server
> > list pointer inside the if-statement. Dealing with other types and
> > versions can be left for when such have been defined.
> >
> > This can be tested by doing the following with KASAN enabled:
> >
> > echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
> >
> > and produces an oops like the following:
> >
> > BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
> > ...
> > Call Trace:
> > <TASK>
> > __dump_stack lib/dump_stack.c:88 [inline]
> > dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> > print_address_description mm/kasan/report.c:377 [inline]
> > print_report+0xc3/0x620 mm/kasan/report.c:488
> > kasan_report+0xd9/0x110 mm/kasan/report.c:601
> > dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > __key_create_or_update+0x453/0xdf0 security/keys/key.c:842
> > key_create_or_update+0x42/0x50 security/keys/key.c:1007
> > __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
> > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > entry_SYSCALL_64_after_hwframe+0x62/0x6a
> >
> > This patch was originally by Edward Adam Davis, but was modified by Linus.
> >
> > Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> > Reported-and-tested-by: [email protected]
> > Link: https://lore.kernel.org/r/[email protected]/
> > Suggested-by: Linus Torvalds <[email protected]>
> > Signed-off-by: Edward Adam Davis <[email protected]>
> > Signed-off-by: David Howells <[email protected]>
> > Tested-by: David Howells <[email protected]>
> > cc: Edward Adam Davis <[email protected]>
> > cc: Simon Horman <[email protected]>
> > cc: Linus Torvalds <[email protected]>
> > cc: Jarkko Sakkinen <[email protected]>
> > cc: Jeffrey E Altman <[email protected]>
> > cc: Wang Lei <[email protected]>
> > cc: Jeff Layton <[email protected]>
> > cc: Steve French <[email protected]>
> > cc: Marc Dionne <[email protected]>
> > cc: "David S. Miller" <[email protected]>
> > cc: Eric Dumazet <[email protected]>
> > cc: Jakub Kicinski <[email protected]>
> > cc: Paolo Abeni <[email protected]>
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > cc: [email protected]
> > ---
> > net/dns_resolver/dns_key.c | 19 +++++++++----------
> > 1 file changed, 9 insertions(+), 10 deletions(-)
> >
> > diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
> > index 2a6d363763a2..f18ca02aa95a 100644
> > --- a/net/dns_resolver/dns_key.c
> > +++ b/net/dns_resolver/dns_key.c
> > @@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
> > static int
> > dns_resolver_preparse(struct key_preparsed_payload *prep)
> > {
> > - const struct dns_server_list_v1_header *v1;
> > - const struct dns_payload_header *bin;
> > struct user_key_payload *upayload;
> > unsigned long derrno;
> > int ret;
> > @@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
> > return -EINVAL;
> >
> > if (data[0] == 0) {
> > + const struct dns_server_list_v1_header *v1;
> > +
> > /* It may be a server list. */
> > - if (datalen <= sizeof(*bin))
> > + if (datalen <= sizeof(*v1))
> > return -EINVAL;
> >
> > - bin = (const struct dns_payload_header *)data;
> > - kenter("[%u,%u],%u", bin->content, bin->version, datalen);
> > - if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > + v1 = (const struct dns_server_list_v1_header *)data;
> > + kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
> > + if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > pr_warn_ratelimited(
> > "dns_resolver: Unsupported content type (%u)\n",
> > - bin->content);
> > + v1->hdr.content);
> > return -EINVAL;
> > }
> >
> > - if (bin->version != 1) {
> > + if (v1->hdr.version != 1) {
> > pr_warn_ratelimited(
> > "dns_resolver: Unsupported server list version (%u)\n",
> > - bin->version);
> > + v1->hdr.version);
> > return -EINVAL;
> > }
> >
> > - v1 = (const struct dns_server_list_v1_header *)bin;
> > if ((v1->status != DNS_LOOKUP_GOOD &&
> > v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
> > if (prep->expiry == TIME64_MAX)
> >
>
> Hi Edward and kernel experts,
>
> Above patch(upstream commit: 1997b3cb4217b09) seems causing a keyctl05 case
> to fail in LTP:
> https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/keyctl/keyctl05.c
>
> It could be reproduced on a bare metal platform.
> Kconfig: https://raw.githubusercontent.com/xupengfe/kconfig_diff/main/config_v6.7-rc8
> Seems general kconfig could reproduce this issue.
>
> Bisected info between v6.7-rc7(keyctl05 passed) and v6.7-rc8(keyctl05 failed)
> is in attached.
>
> keyctl05 failed in add_key with type "dns_resolver" syscall step tracked
> by strace:
> "
> [pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> [pid 863106] <... alarm resumed>) = 30
> [pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
> "
>
> Passed behavior in v6.7-rc7 kernel:
> "
> [pid 6726] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> [pid 6725] rt_sigreturn({mask=[]}) = 61
> [pid 6726] <... add_key resumed>) = 1029222644
> "
Sorry, updated more keyctl05 failed in add_key with type "dns_resolver"
syscall step tracked by strace:
"
[pid 863107] getppid() = 863106
[pid 863107] kill(863106, SIGUSR1) = 0
[pid 863106] <... wait4 resumed>0x7ffc5ec94858, 0, NULL) = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
[pid 863107] keyctl(KEYCTL_JOIN_SESSION_KEYRING, NULL <unfinished ...>
[pid 863106] --- SIGUSR1 {si_signo=SIGUSR1, si_code=SI_USER, si_pid=863107, si_uid=0} ---
[pid 863107] <... keyctl resumed>) = 512571383
[pid 863106] alarm(30 <unfinished ...>
[pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
[pid 863106] <... alarm resumed>) = 30
[pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
[pid 863106] rt_sigreturn({mask=[]} <unfinished ...>
[pid 863107] write(2, "keyctl05.c:114: TFAIL: unexpecte"..., 79keyctl05.c:114: TFAIL: unexpected error adding 'dns_resolver' key: EINVAL (22)
<unfinished ...>
[pid 863106] <... rt_sigreturn resumed>) = 61
[pid 863107] <... write resumed>) = 79
"
Passed behavior in v6.7-rc7 kernel:
"
[pid 6726] getppid() = 6725
[pid 6726] kill(6725, SIGUSR1 <unfinished ...>
[pid 6725] <... wait4 resumed>0x7ffc6cad1c68, 0, NULL) = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
[pid 6726] <... kill resumed>) = 0
[pid 6725] --- SIGUSR1 {si_signo=SIGUSR1, si_code=SI_USER, si_pid=6726, si_uid=0} ---
[pid 6726] keyctl(KEYCTL_JOIN_SESSION_KEYRING, NULL <unfinished ...>
[pid 6725] alarm(30 <unfinished ...>
[pid 6726] <... keyctl resumed>) = 713868472
[pid 6725] <... alarm resumed>) = 30
[pid 6726] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
[pid 6725] rt_sigreturn({mask=[]}) = 61
[pid 6726] <... add_key resumed>) = 1029222644
"
>
> Do you mind to take a look for above issue?
>
> Best Regards,
> Thanks!
> git bisect start
> # status: waiting for both good and bad commits
> # good: [861deac3b092f37b2c5e6871732f3e11486f7082] Linux 6.7-rc7
> git bisect good 861deac3b092f37b2c5e6871732f3e11486f7082
> # status: waiting for bad commit, 1 good commit known
> # bad: [610a9b8f49fbcf1100716370d3b5f6f884a2835a] Linux 6.7-rc8
> git bisect bad 610a9b8f49fbcf1100716370d3b5f6f884a2835a
> # good: [861deac3b092f37b2c5e6871732f3e11486f7082] Linux 6.7-rc7
> git bisect good 861deac3b092f37b2c5e6871732f3e11486f7082
> # bad: [505e701c0b2cfa9e34811020829759b7663a604c] Merge tag 'kbuild-fixes-v6.7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
> git bisect bad 505e701c0b2cfa9e34811020829759b7663a604c
> # good: [1803d0c5ee1a3bbee23db2336e21add067824f02] mailmap: add an old address for Naoya Horiguchi
> git bisect good 1803d0c5ee1a3bbee23db2336e21add067824f02
> # bad: [eeec2599630ac1ac03db98f3ba976975c72a1427] Merge tag 'bcachefs-2023-12-27' of https://evilpiepirate.org/git/bcachefs
> git bisect bad eeec2599630ac1ac03db98f3ba976975c72a1427
> # bad: [f5837722ffecbbedf1b1dbab072a063565f0dad1] Merge tag 'mm-hotfixes-stable-2023-12-27-15-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> git bisect bad f5837722ffecbbedf1b1dbab072a063565f0dad1
> # good: [b8e0792449928943c15d1af9f63816911d139267] virtio_blk: fix snprintf truncation compiler warning
> git bisect good b8e0792449928943c15d1af9f63816911d139267
> # bad: [1997b3cb4217b09e49659b634c94da47f0340409] keys, dns: Fix missing size check of V1 server-list header
> git bisect bad 1997b3cb4217b09e49659b634c94da47f0340409
> # good: [fbafc3e621c3f4ded43720fdb1d6ce1728ec664e] Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
> git bisect good fbafc3e621c3f4ded43720fdb1d6ce1728ec664e
> # first bad commit: [1997b3cb4217b09e49659b634c94da47f0340409] keys, dns: Fix missing size check of V1 server-list header
On 2024-01-10 at 13:19:49 +0800, Edward Adam Davis wrote:
> On Wed, 10 Jan 2024 12:40:41 +0800, Pengfei Xu wrote:
> > > Hi Linus, Edward,
> > >
> > > Here's Linus's patch dressed up with a commit message. I would marginally
> > > prefer just to insert the missing size check, but I'm also fine with Linus's
> > > approach for now until we have different content types or newer versions.
> > >
> > > Note that I'm not sure whether I should require Linus's S-o-b since he made
> > > modifications or whether I should use a Codeveloped-by line for him.
> > >
> > > David
> > > ---
> > > From: Edward Adam Davis <[email protected]>
> > >
> > > keys, dns: Fix missing size check of V1 server-list header
> > >
> > > The dns_resolver_preparse() function has a check on the size of the payload
> > > for the basic header of the binary-style payload, but is missing a check
> > > for the size of the V1 server-list payload header after determining that's
> > > what we've been given.
> > >
> > > Fix this by getting rid of the the pointer to the basic header and just
> > > assuming that we have a V1 server-list payload and moving the V1 server
> > > list pointer inside the if-statement. Dealing with other types and
> > > versions can be left for when such have been defined.
> > >
> > > This can be tested by doing the following with KASAN enabled:
> > >
> > > echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
> > >
> > > and produces an oops like the following:
> > >
> > > BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > > Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
> > > ...
> > > Call Trace:
> > > <TASK>
> > > __dump_stack lib/dump_stack.c:88 [inline]
> > > dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
> > > print_address_description mm/kasan/report.c:377 [inline]
> > > print_report+0xc3/0x620 mm/kasan/report.c:488
> > > kasan_report+0xd9/0x110 mm/kasan/report.c:601
> > > dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
> > > __key_create_or_update+0x453/0xdf0 security/keys/key.c:842
> > > key_create_or_update+0x42/0x50 security/keys/key.c:1007
> > > __do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
> > > do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> > > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
> > > entry_SYSCALL_64_after_hwframe+0x62/0x6a
> > >
> > > This patch was originally by Edward Adam Davis, but was modified by Linus.
> > >
> > > Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
> > > Reported-and-tested-by: [email protected]
> > > Link: https://lore.kernel.org/r/[email protected]/
> > > Suggested-by: Linus Torvalds <[email protected]>
> > > Signed-off-by: Edward Adam Davis <[email protected]>
> > > Signed-off-by: David Howells <[email protected]>
> > > Tested-by: David Howells <[email protected]>
> > > cc: Edward Adam Davis <[email protected]>
> > > cc: Simon Horman <[email protected]>
> > > cc: Linus Torvalds <[email protected]>
> > > cc: Jarkko Sakkinen <[email protected]>
> > > cc: Jeffrey E Altman <[email protected]>
> > > cc: Wang Lei <[email protected]>
> > > cc: Jeff Layton <[email protected]>
> > > cc: Steve French <[email protected]>
> > > cc: Marc Dionne <[email protected]>
> > > cc: "David S. Miller" <[email protected]>
> > > cc: Eric Dumazet <[email protected]>
> > > cc: Jakub Kicinski <[email protected]>
> > > cc: Paolo Abeni <[email protected]>
> > > cc: [email protected]
> > > cc: [email protected]
> > > cc: [email protected]
> > > cc: [email protected]
> > > cc: [email protected]
> > > cc: [email protected]
> > > ---
> > > net/dns_resolver/dns_key.c | 19 +++++++++----------
> > > 1 file changed, 9 insertions(+), 10 deletions(-)
> > >
> > > diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
> > > index 2a6d363763a2..f18ca02aa95a 100644
> > > --- a/net/dns_resolver/dns_key.c
> > > +++ b/net/dns_resolver/dns_key.c
> > > @@ -91,8 +91,6 @@ const struct cred *dns_resolver_cache;
> > > static int
> > > dns_resolver_preparse(struct key_preparsed_payload *prep)
> > > {
> > > - const struct dns_server_list_v1_header *v1;
> > > - const struct dns_payload_header *bin;
> > > struct user_key_payload *upayload;
> > > unsigned long derrno;
> > > int ret;
> > > @@ -103,27 +101,28 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
> > > return -EINVAL;
> > >
> > > if (data[0] == 0) {
> > > + const struct dns_server_list_v1_header *v1;
> > > +
> > > /* It may be a server list. */
> > > - if (datalen <= sizeof(*bin))
> > > + if (datalen <= sizeof(*v1))
> > > return -EINVAL;
> > >
> > > - bin = (const struct dns_payload_header *)data;
> > > - kenter("[%u,%u],%u", bin->content, bin->version, datalen);
> > > - if (bin->content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > > + v1 = (const struct dns_server_list_v1_header *)data;
> > > + kenter("[%u,%u],%u", v1->hdr.content, v1->hdr.version, datalen);
> > > + if (v1->hdr.content != DNS_PAYLOAD_IS_SERVER_LIST) {
> > > pr_warn_ratelimited(
> > > "dns_resolver: Unsupported content type (%u)\n",
> > > - bin->content);
> > > + v1->hdr.content);
> > > return -EINVAL;
> > > }
> > >
> > > - if (bin->version != 1) {
> > > + if (v1->hdr.version != 1) {
> > > pr_warn_ratelimited(
> > > "dns_resolver: Unsupported server list version (%u)\n",
> > > - bin->version);
> > > + v1->hdr.version);
> > > return -EINVAL;
> > > }
> > >
> > > - v1 = (const struct dns_server_list_v1_header *)bin;
> > > if ((v1->status != DNS_LOOKUP_GOOD &&
> > > v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) {
> > > if (prep->expiry == TIME64_MAX)
> > >
> >
> > Hi Edward and kernel experts,
> >
> > Above patch(upstream commit: 1997b3cb4217b09) seems causing a keyctl05 case
> > to fail in LTP:
> > https://github.com/linux-test-project/ltp/blob/master/testcases/kernel/syscalls/keyctl/keyctl05.c
> >
> > It could be reproduced on a bare metal platform.
> > Kconfig: https://raw.githubusercontent.com/xupengfe/kconfig_diff/main/config_v6.7-rc8
> > Seems general kconfig could reproduce this issue.
> >
> > Bisected info between v6.7-rc7(keyctl05 passed) and v6.7-rc8(keyctl05 failed)
> > is in attached.
> >
> > keyctl05 failed in add_key with type "dns_resolver" syscall step tracked
> > by strace:
> > "
> > [pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> > [pid 863106] <... alarm resumed>) = 30
> > [pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
> The reason for the failure of add_key() is that the length of the incoming data
> is 5, which is less than sizeof(*v1), so keyctl05.c failed.
> Suggest modifying keyctl05.c to increase the length of the incoming data to 6
> bytes or more.
Thanks for your suggestion!
dns_server_list_v1_header struct is 6 u8 data instead of previous bin.
After increased the dns_res_payload to 7 bytes(6 bytes was still failed),
keyctl05 could be passed.
"
static char dns_res_payload[] = { 0x00, 0x00, 0x01, 0xff, 0x00, 0x00, 0x00 };
"
I will improve the case in LTP.
Thanks!
> > "
> >
> > Passed behavior in v6.7-rc7 kernel:
> > "
> > [pid 6726] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> > [pid 6725] rt_sigreturn({mask=[]}) = 61
> > [pid 6726] <... add_key resumed>) = 1029222644
> > "
> >
> > Do you mind to take a look for above issue?
> Edward,
> BR
>
On 2024-01-10 at 10:14:28 +0000, David Howells wrote:
> Pengfei Xu <[email protected]> wrote:
>
> > Bisected info between v6.7-rc7(keyctl05 passed) and v6.7-rc8(keyctl05 failed)
> > is in attached.
> >
> > keyctl05 failed in add_key with type "dns_resolver" syscall step tracked
> > by strace:
> > "
> > [pid 863107] add_key("dns_resolver", "desc", "\0\0\1\377\0", 5, KEY_SPEC_SESSION_KEYRING <unfinished ...>
> > [pid 863106] <... alarm resumed>) = 30
> > [pid 863107] <... add_key resumed>) = -1 EINVAL (Invalid argument)
> > "
>
> It should fail as the payload is actually invalid. The payload specifies a
> version 1 format - and that requires a 6-byte header. The bug the patched
> fixes is that whilst there is a length check for the basic 3-byte header,
> there was no length check for the extended v1 header.
Thanks for description!
>
> > After increased the dns_res_payload to 7 bytes(6 bytes was still failed),
>
> The following doesn't work for you?
>
> echo -n -e '\0\0\01\xff\0\0' | keyctl padd dns_resolver desc @p
I tried as follows, 6 bytes failed and 7 bytes passed:
"
# echo -n -e '\0\0\01\xff\0\0' | keyctl padd dns_resolver desc @p
add_key: Invalid argument
# echo -n -e '\0\0\01\xff\0\0\0' | keyctl padd dns_resolver desc @p
74678921
# uname -r
6.7.0-rc8
"
Thanks!
>
> David
>
Meh. Does the attached fix it for you?
David
---
diff --git a/net/dns_resolver/dns_key.c b/net/dns_resolver/dns_key.c
index f18ca02aa95a..c42ddd85ff1f 100644
--- a/net/dns_resolver/dns_key.c
+++ b/net/dns_resolver/dns_key.c
@@ -104,7 +104,7 @@ dns_resolver_preparse(struct key_preparsed_payload *prep)
const struct dns_server_list_v1_header *v1;
/* It may be a server list. */
- if (datalen <= sizeof(*v1))
+ if (datalen < sizeof(*v1))
return -EINVAL;
v1 = (const struct dns_server_list_v1_header *)data;
On Wed, 10 Jan 2024 at 09:23, David Howells <[email protected]> wrote:
>
> Meh. Does the attached fix it for you?
Bah. Obvious fix is obvious.
Mind sending it as a proper patch with sign-off etc, and we'll get
this fixed and marked for stable.
Linus