One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element arrays with flexible-array
member in structs negotiate_req and extended_response, and refactor the
rest of the code, accordingly.
Also, make use of the DECLARE_FLEX_ARRAY() helper to declare flexible
array member EncryptionKey in union u. This new helper allows for
flexible-array members in unions.
Change pointer notation to proper array notation in a call to memcpy()
where flexible-array member DialectsArray is being used as destination
argument.
Important to mention is that doing a build before/after this patch results
in no binary output differences.
This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].
Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/229
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
fs/cifs/cifspdu.h | 7 ++++---
fs/cifs/cifssmb.c | 2 +-
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
index aeba371c4c70..d1abaeea974a 100644
--- a/fs/cifs/cifspdu.h
+++ b/fs/cifs/cifspdu.h
@@ -483,7 +483,7 @@ put_bcc(__u16 count, struct smb_hdr *hdr)
typedef struct negotiate_req {
struct smb_hdr hdr; /* wct = 0 */
__le16 ByteCount;
- unsigned char DialectsArray[1];
+ unsigned char DialectsArray[];
} __attribute__((packed)) NEGOTIATE_REQ;
#define MIN_TZ_ADJ (15 * 60) /* minimum grid for timezones in seconds */
@@ -508,13 +508,14 @@ typedef struct negotiate_rsp {
__u8 EncryptionKeyLength;
__u16 ByteCount;
union {
- unsigned char EncryptionKey[1]; /* cap extended security off */
+ /* cap extended security off */
+ DECLARE_FLEX_ARRAY(unsigned char, EncryptionKey);
/* followed by Domain name - if extended security is off */
/* followed by 16 bytes of server GUID */
/* then security blob if cap_extended_security negotiated */
struct {
unsigned char GUID[SMB1_CLIENT_GUID_SIZE];
- unsigned char SecurityBlob[1];
+ unsigned char SecurityBlob[];
} __attribute__((packed)) extended_response;
} __attribute__((packed)) u;
} __attribute__((packed)) NEGOTIATE_RSP;
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 7aa91e272027..7a808e41b1b8 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -465,7 +465,7 @@ CIFSSMBNegotiate(const unsigned int xid,
for (i = 0; i < CIFS_NUM_PROT; i++) {
size_t len = strlen(protocols[i].name) + 1;
- memcpy(pSMB->DialectsArray+count, protocols[i].name, len);
+ memcpy(&pSMB->DialectsArray[count], protocols[i].name, len);
count += len;
}
inc_rfc1001_len(pSMB, count);
--
2.34.1
On Tue, Oct 04, 2022 at 08:51:39PM -0500, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element arrays with flexible-array
> member in structs negotiate_req and extended_response, and refactor the
> rest of the code, accordingly.
>
> Also, make use of the DECLARE_FLEX_ARRAY() helper to declare flexible
> array member EncryptionKey in union u. This new helper allows for
> flexible-array members in unions.
>
> Change pointer notation to proper array notation in a call to memcpy()
> where flexible-array member DialectsArray is being used as destination
> argument.
>
> Important to mention is that doing a build before/after this patch results
> in no binary output differences.
>
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/229
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
Looks good to me; thanks!
Reviewed-by: Kees Cook <[email protected]>
--
Kees Cook
On Wed, 5 Oct 2022 at 12:31, Gustavo A. R. Silva <[email protected]> wrote:
>
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element arrays with flexible-array
> member in structs negotiate_req and extended_response, and refactor the
> rest of the code, accordingly.
>
> Also, make use of the DECLARE_FLEX_ARRAY() helper to declare flexible
> array member EncryptionKey in union u. This new helper allows for
> flexible-array members in unions.
>
> Change pointer notation to proper array notation in a call to memcpy()
> where flexible-array member DialectsArray is being used as destination
> argument.
>
> Important to mention is that doing a build before/after this patch results
> in no binary output differences.
Looks good to me.
Reviewed-by me
Thanks for verifying that it does not change the binary utput.
>
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
>
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/229
> Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
> Signed-off-by: Gustavo A. R. Silva <[email protected]>
> ---
> fs/cifs/cifspdu.h | 7 ++++---
> fs/cifs/cifssmb.c | 2 +-
> 2 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/cifspdu.h b/fs/cifs/cifspdu.h
> index aeba371c4c70..d1abaeea974a 100644
> --- a/fs/cifs/cifspdu.h
> +++ b/fs/cifs/cifspdu.h
> @@ -483,7 +483,7 @@ put_bcc(__u16 count, struct smb_hdr *hdr)
> typedef struct negotiate_req {
> struct smb_hdr hdr; /* wct = 0 */
> __le16 ByteCount;
> - unsigned char DialectsArray[1];
> + unsigned char DialectsArray[];
> } __attribute__((packed)) NEGOTIATE_REQ;
>
> #define MIN_TZ_ADJ (15 * 60) /* minimum grid for timezones in seconds */
> @@ -508,13 +508,14 @@ typedef struct negotiate_rsp {
> __u8 EncryptionKeyLength;
> __u16 ByteCount;
> union {
> - unsigned char EncryptionKey[1]; /* cap extended security off */
> + /* cap extended security off */
> + DECLARE_FLEX_ARRAY(unsigned char, EncryptionKey);
> /* followed by Domain name - if extended security is off */
> /* followed by 16 bytes of server GUID */
> /* then security blob if cap_extended_security negotiated */
> struct {
> unsigned char GUID[SMB1_CLIENT_GUID_SIZE];
> - unsigned char SecurityBlob[1];
> + unsigned char SecurityBlob[];
> } __attribute__((packed)) extended_response;
> } __attribute__((packed)) u;
> } __attribute__((packed)) NEGOTIATE_RSP;
> diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> index 7aa91e272027..7a808e41b1b8 100644
> --- a/fs/cifs/cifssmb.c
> +++ b/fs/cifs/cifssmb.c
> @@ -465,7 +465,7 @@ CIFSSMBNegotiate(const unsigned int xid,
> for (i = 0; i < CIFS_NUM_PROT; i++) {
> size_t len = strlen(protocols[i].name) + 1;
>
> - memcpy(pSMB->DialectsArray+count, protocols[i].name, len);
> + memcpy(&pSMB->DialectsArray[count], protocols[i].name, len);
> count += len;
> }
> inc_rfc1001_len(pSMB, count);
> --
> 2.34.1
>
merged into cifs-2.6.git for-next
On Tue, Oct 4, 2022 at 10:17 PM Kees Cook <[email protected]> wrote:
>
> On Tue, Oct 04, 2022 at 08:51:39PM -0500, Gustavo A. R. Silva wrote:
> > One-element arrays are deprecated, and we are replacing them with flexible
> > array members instead. So, replace one-element arrays with flexible-array
> > member in structs negotiate_req and extended_response, and refactor the
> > rest of the code, accordingly.
> >
> > Also, make use of the DECLARE_FLEX_ARRAY() helper to declare flexible
> > array member EncryptionKey in union u. This new helper allows for
> > flexible-array members in unions.
> >
> > Change pointer notation to proper array notation in a call to memcpy()
> > where flexible-array member DialectsArray is being used as destination
> > argument.
> >
> > Important to mention is that doing a build before/after this patch results
> > in no binary output differences.
> >
> > This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> > routines on memcpy() and help us make progress towards globally
> > enabling -fstrict-flex-arrays=3 [1].
> >
> > Link: https://github.com/KSPP/linux/issues/79
> > Link: https://github.com/KSPP/linux/issues/229
> > Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
> > Signed-off-by: Gustavo A. R. Silva <[email protected]>
>
> Looks good to me; thanks!
>
> Reviewed-by: Kees Cook <[email protected]>
>
> --
> Kees Cook
--
Thanks,
Steve