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hfsplus: fix out-of-bounds warnings in __hfsplus_setxattr
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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.

Matthew said:

: 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.

Link: KSPP/linux#109
Link: https://lkml.kernel.org/r/20210330145226.GA207011@embeddedor
Signed-off-by: Gustavo A. R. Silva <[email protected]>
Reported-by: kernel test robot <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Stephen Rothwell <[email protected]>
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@GustavoARSilva @sfrothwell
GustavoARSilva authored and sfrothwell committed Aug 9, 2021
1 parent ee33889 commit 3cb4dc3
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Showing 4 changed files with 26 additions and 24 deletions.
16 changes: 8 additions & 8 deletions fs/hfsplus/catalog.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -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 &
Expand All @@ -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;
Expand Down
4 changes: 2 additions & 2 deletions fs/hfsplus/dir.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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 ==
Expand Down
12 changes: 8 additions & 4 deletions fs/hfsplus/hfsplus_raw.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand Down Expand Up @@ -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;

Expand Down
18 changes: 8 additions & 10 deletions fs/hfsplus/xattr.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -261,10 +261,8 @@ 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)) ||
Expand Down Expand Up @@ -296,7 +294,7 @@ 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,
Expand All @@ -309,7 +307,7 @@ 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,
Expand Down Expand Up @@ -462,14 +460,14 @@ 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;
Expand Down Expand Up @@ -630,14 +628,14 @@ 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 {
Expand Down

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