Fix the following out-of-bounds warnings by enclosing
structure members file and finder into new struct info:
fs/hfsplus/xattr.c:300:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct DInfo' at offset 48 [-Warray-bounds]
fs/hfsplus/xattr.c:313:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct FInfo' at offset 48 [-Warray-bounds]
Refactor the code by making it more "structured."
Also, this helps with the ongoing efforts to enable -Warray-bounds and
makes the code clearer and avoid confusing the compiler.
Link: https://github.com/KSPP/linux/issues/109
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Gustavo A. R. Silva <[email protected]>
---
fs/hfsplus/catalog.c | 16 ++++++++--------
fs/hfsplus/dir.c | 4 ++--
fs/hfsplus/hfsplus_raw.h | 12 ++++++++----
fs/hfsplus/xattr.c | 18 ++++++++----------
4 files changed, 26 insertions(+), 24 deletions(-)
diff --git a/fs/hfsplus/catalog.c b/fs/hfsplus/catalog.c
index 35472cba750e..9cdc6550b468 100644
--- a/fs/hfsplus/catalog.c
+++ b/fs/hfsplus/catalog.c
@@ -124,7 +124,7 @@ static int hfsplus_cat_build_record(hfsplus_cat_entry *entry,
hfsplus_cat_set_perms(inode, &folder->permissions);
if (inode == sbi->hidden_dir)
/* invisible and namelocked */
- folder->user_info.frFlags = cpu_to_be16(0x5000);
+ folder->info.user.frFlags = cpu_to_be16(0x5000);
return sizeof(*folder);
} else {
struct hfsplus_cat_file *file;
@@ -142,14 +142,14 @@ static int hfsplus_cat_build_record(hfsplus_cat_entry *entry,
if (cnid == inode->i_ino) {
hfsplus_cat_set_perms(inode, &file->permissions);
if (S_ISLNK(inode->i_mode)) {
- file->user_info.fdType =
+ file->info.user.fdType =
cpu_to_be32(HFSP_SYMLINK_TYPE);
- file->user_info.fdCreator =
+ file->info.user.fdCreator =
cpu_to_be32(HFSP_SYMLINK_CREATOR);
} else {
- file->user_info.fdType =
+ file->info.user.fdType =
cpu_to_be32(sbi->type);
- file->user_info.fdCreator =
+ file->info.user.fdCreator =
cpu_to_be32(sbi->creator);
}
if (HFSPLUS_FLG_IMMUTABLE &
@@ -158,11 +158,11 @@ static int hfsplus_cat_build_record(hfsplus_cat_entry *entry,
file->flags |=
cpu_to_be16(HFSPLUS_FILE_LOCKED);
} else {
- file->user_info.fdType =
+ file->info.user.fdType =
cpu_to_be32(HFSP_HARDLINK_TYPE);
- file->user_info.fdCreator =
+ file->info.user.fdCreator =
cpu_to_be32(HFSP_HFSPLUS_CREATOR);
- file->user_info.fdFlags =
+ file->info.user.fdFlags =
cpu_to_be16(0x100);
file->create_date =
HFSPLUS_I(sbi->hidden_dir)->create_date;
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c
index 03e6c046faf4..0ae8f797d7f3 100644
--- a/fs/hfsplus/dir.c
+++ b/fs/hfsplus/dir.c
@@ -73,9 +73,9 @@ static struct dentry *hfsplus_lookup(struct inode *dir, struct dentry *dentry,
goto fail;
}
cnid = be32_to_cpu(entry.file.id);
- if (entry.file.user_info.fdType ==
+ if (entry.file.info.user.fdType ==
cpu_to_be32(HFSP_HARDLINK_TYPE) &&
- entry.file.user_info.fdCreator ==
+ entry.file.info.user.fdCreator ==
cpu_to_be32(HFSP_HFSPLUS_CREATOR) &&
HFSPLUS_SB(sb)->hidden_dir &&
(entry.file.create_date ==
diff --git a/fs/hfsplus/hfsplus_raw.h b/fs/hfsplus/hfsplus_raw.h
index 456e87aec7fd..005a043bc7ee 100644
--- a/fs/hfsplus/hfsplus_raw.h
+++ b/fs/hfsplus/hfsplus_raw.h
@@ -260,8 +260,10 @@ struct hfsplus_cat_folder {
__be32 access_date;
__be32 backup_date;
struct hfsplus_perm permissions;
- struct DInfo user_info;
- struct DXInfo finder_info;
+ struct {
+ struct DInfo user;
+ struct DXInfo finder;
+ } info;
__be32 text_encoding;
__be32 subfolders; /* Subfolder count in HFSX. Reserved in HFS+. */
} __packed;
@@ -294,8 +296,10 @@ struct hfsplus_cat_file {
__be32 access_date;
__be32 backup_date;
struct hfsplus_perm permissions;
- struct FInfo user_info;
- struct FXInfo finder_info;
+ struct {
+ struct FInfo user;
+ struct FXInfo finder;
+ } info;
__be32 text_encoding;
u32 reserved2;
diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c
index 4d169c5a2673..e18a472ac937 100644
--- a/fs/hfsplus/xattr.c
+++ b/fs/hfsplus/xattr.c
@@ -262,10 +262,8 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
struct hfs_find_data cat_fd;
hfsplus_cat_entry entry;
u16 cat_entry_flags, cat_entry_type;
- u16 folder_finderinfo_len = sizeof(struct DInfo) +
- sizeof(struct DXInfo);
- u16 file_finderinfo_len = sizeof(struct FInfo) +
- sizeof(struct FXInfo);
+ u16 folder_finderinfo_len = sizeof(entry.folder.info);
+ u16 file_finderinfo_len = sizeof(entry.file.info);
if ((!S_ISREG(inode->i_mode) &&
!S_ISDIR(inode->i_mode)) ||
@@ -297,7 +295,7 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
sizeof(hfsplus_cat_entry));
if (be16_to_cpu(entry.type) == HFSPLUS_FOLDER) {
if (size == folder_finderinfo_len) {
- memcpy(&entry.folder.user_info, value,
+ memcpy(&entry.folder.info, value,
folder_finderinfo_len);
hfs_bnode_write(cat_fd.bnode, &entry,
cat_fd.entryoffset,
@@ -310,7 +308,7 @@ int __hfsplus_setxattr(struct inode *inode, const char *name,
}
} else if (be16_to_cpu(entry.type) == HFSPLUS_FILE) {
if (size == file_finderinfo_len) {
- memcpy(&entry.file.user_info, value,
+ memcpy(&entry.file.info, value,
file_finderinfo_len);
hfs_bnode_write(cat_fd.bnode, &entry,
cat_fd.entryoffset,
@@ -463,14 +461,14 @@ static ssize_t hfsplus_getxattr_finder_info(struct inode *inode,
if (entry_type == HFSPLUS_FOLDER) {
hfs_bnode_read(fd.bnode, folder_finder_info,
fd.entryoffset +
- offsetof(struct hfsplus_cat_folder, user_info),
+ offsetof(struct hfsplus_cat_folder, info.user),
folder_rec_len);
memcpy(value, folder_finder_info, folder_rec_len);
res = folder_rec_len;
} else if (entry_type == HFSPLUS_FILE) {
hfs_bnode_read(fd.bnode, file_finder_info,
fd.entryoffset +
- offsetof(struct hfsplus_cat_file, user_info),
+ offsetof(struct hfsplus_cat_file, info.user),
file_rec_len);
memcpy(value, file_finder_info, file_rec_len);
res = file_rec_len;
@@ -631,14 +629,14 @@ static ssize_t hfsplus_listxattr_finder_info(struct dentry *dentry,
len = sizeof(struct DInfo) + sizeof(struct DXInfo);
hfs_bnode_read(fd.bnode, folder_finder_info,
fd.entryoffset +
- offsetof(struct hfsplus_cat_folder, user_info),
+ offsetof(struct hfsplus_cat_folder, info.user),
len);
found_bit = find_first_bit((void *)folder_finder_info, len*8);
} else if (entry_type == HFSPLUS_FILE) {
len = sizeof(struct FInfo) + sizeof(struct FXInfo);
hfs_bnode_read(fd.bnode, file_finder_info,
fd.entryoffset +
- offsetof(struct hfsplus_cat_file, user_info),
+ offsetof(struct hfsplus_cat_file, info.user),
len);
found_bit = find_first_bit((void *)file_finder_info, len*8);
} else {
--
2.27.0
On Tue, 30 Mar 2021 09:52:26 -0500 "Gustavo A. R. Silva" <[email protected]> wrote:
> Fix the following out-of-bounds warnings by enclosing
> structure members file and finder into new struct info:
>
> fs/hfsplus/xattr.c:300:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct DInfo' at offset 48 [-Warray-bounds]
> fs/hfsplus/xattr.c:313:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct FInfo' at offset 48 [-Warray-bounds]
>
> Refactor the code by making it more "structured."
>
> Also, this helps with the ongoing efforts to enable -Warray-bounds and
> makes the code clearer and avoid confusing the compiler.
Confused. What was wrong with the old code? Was this warning
legitimate and if so, why? Or is this patch a workaround for a
compiler shortcoming?
On Tue, Mar 30, 2021 at 09:43:20PM -0700, Andrew Morton wrote:
> On Tue, 30 Mar 2021 09:52:26 -0500 "Gustavo A. R. Silva" <[email protected]> wrote:
>
> > Fix the following out-of-bounds warnings by enclosing
> > structure members file and finder into new struct info:
> >
> > fs/hfsplus/xattr.c:300:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct DInfo' at offset 48 [-Warray-bounds]
> > fs/hfsplus/xattr.c:313:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct FInfo' at offset 48 [-Warray-bounds]
> >
> > Refactor the code by making it more "structured."
> >
> > Also, this helps with the ongoing efforts to enable -Warray-bounds and
> > makes the code clearer and avoid confusing the compiler.
>
> Confused. What was wrong with the old code? Was this warning
> legitimate and if so, why? Or is this patch a workaround for a
> compiler shortcoming?
The offending line is this:
- memcpy(&entry.file.user_info, value,
+ memcpy(&entry.file.info, value,
file_finderinfo_len);
what it's trying to do is copy two structs which are adjacent to each
other in a single call to memcpy(). gcc legitimately complains that the
memcpy to this struct overruns the bounds of the struct. What Gustavo
has done here is introduce a new struct that contains the two structs,
and now gcc is happy that the memcpy doesn't overrun the length of this
containing struct.
On 3/30/21 23:53, Matthew Wilcox wrote:
> On Tue, Mar 30, 2021 at 09:43:20PM -0700, Andrew Morton wrote:
>> On Tue, 30 Mar 2021 09:52:26 -0500 "Gustavo A. R. Silva" <[email protected]> wrote:
>>
>>> Fix the following out-of-bounds warnings by enclosing
>>> structure members file and finder into new struct info:
>>>
>>> fs/hfsplus/xattr.c:300:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct DInfo' at offset 48 [-Warray-bounds]
>>> fs/hfsplus/xattr.c:313:5: warning: 'memcpy' offset [65, 80] from the object at 'entry' is out of the bounds of referenced subobject 'user_info' with type 'struct FInfo' at offset 48 [-Warray-bounds]
>>>
>>> Refactor the code by making it more "structured."
>>>
>>> Also, this helps with the ongoing efforts to enable -Warray-bounds and
>>> makes the code clearer and avoid confusing the compiler.
>>
>> Confused. What was wrong with the old code? Was this warning
>> legitimate and if so, why? Or is this patch a workaround for a
>> compiler shortcoming?
>
> The offending line is this:
>
> - memcpy(&entry.file.user_info, value,
> + memcpy(&entry.file.info, value,
> file_finderinfo_len);
>
> what it's trying to do is copy two structs which are adjacent to each
> other in a single call to memcpy(). gcc legitimately complains that the
> memcpy to this struct overruns the bounds of the struct. What Gustavo
> has done here is introduce a new struct that contains the two structs,
> and now gcc is happy that the memcpy doesn't overrun the length of this
> containing struct.
Thanks for this, Matthew. :)
--
Gustavo