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authorGustavo A. R. Silva <gustavoars@kernel.org>2023-07-14 22:56:37 +0300
committerGustavo A. R. Silva <gustavoars@kernel.org>2023-07-31 23:55:48 +0300
commit4d8cbf6dbcdaebe949461b0a933ae4c71cb53edc (patch)
tree87ec646a30ac2a467e6cbed145b09b33b9b8ef25 /fs/omfs/file.c
parent221a4b56ec70c1a9f09ce78751613d16c508a4ce (diff)
downloadlinux-4d8cbf6dbcdaebe949461b0a933ae4c71cb53edc.tar.xz
fs: omfs: Use flexible-array member in struct omfs_extent
Memory for 'struct omfs_extent' and a 'e_extent_count' number of extent entries is indirectly allocated through 'bh->b_data', which is a pointer to data within the page. This implies that the member 'e_entry' (which is the start of extent entries) functions more like an array than a single object of type 'struct omfs_extent_entry'. So we better turn this object into a proper array, in this case a flexible-array member, and with that, fix the following -Wstringop-overflow warning seen after building s390 architecture with allyesconfig (GCC 13): fs/omfs/file.c: In function 'omfs_grow_extent': include/linux/fortify-string.h:57:33: warning: writing 16 bytes into a region of size 0 [-Wstringop-overflow=] 57 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:648:9: note: in expansion of macro '__underlying_memcpy' 648 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:693:26: note: in expansion of macro '__fortify_memcpy_chk' 693 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ fs/omfs/file.c:170:9: note: in expansion of macro 'memcpy' 170 | memcpy(terminator, entry, sizeof(struct omfs_extent_entry)); | ^~~~~~ In file included from fs/omfs/omfs.h:8, from fs/omfs/file.c:11: fs/omfs/omfs_fs.h:80:34: note: at offset 16 into destination object 'e_entry' of size 16 80 | struct omfs_extent_entry e_entry; /* start of extent entries */ | ^~~~~~~ There are some binary differences before and after changes, but this are expected due to the change in the size of 'struct omfs_extent' and the necessary adjusments. This helps with the ongoing efforts to globally enable -Wstringop-overflow. Link: https://github.com/KSPP/linux/issues/330 Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Diffstat (limited to 'fs/omfs/file.c')
-rw-r--r--fs/omfs/file.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/omfs/file.c b/fs/omfs/file.c
index de8f57ee39ec..6b580b9da8e3 100644
--- a/fs/omfs/file.c
+++ b/fs/omfs/file.c
@@ -14,7 +14,7 @@ static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
{
return (sbi->s_sys_blocksize - offset -
sizeof(struct omfs_extent)) /
- sizeof(struct omfs_extent_entry) + 1;
+ sizeof(struct omfs_extent_entry);
}
void omfs_make_empty_table(struct buffer_head *bh, int offset)
@@ -24,8 +24,8 @@ void omfs_make_empty_table(struct buffer_head *bh, int offset)
oe->e_next = ~cpu_to_be64(0ULL);
oe->e_extent_count = cpu_to_be32(1),
oe->e_fill = cpu_to_be32(0x22),
- oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);
- oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);
+ oe->e_entry[0].e_cluster = ~cpu_to_be64(0ULL);
+ oe->e_entry[0].e_blocks = ~cpu_to_be64(0ULL);
}
int omfs_shrink_inode(struct inode *inode)
@@ -68,7 +68,7 @@ int omfs_shrink_inode(struct inode *inode)
last = next;
next = be64_to_cpu(oe->e_next);
- entry = &oe->e_entry;
+ entry = oe->e_entry;
/* ignore last entry as it is the terminator */
for (; extent_count > 1; extent_count--) {
@@ -117,7 +117,7 @@ static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe,
u64 *ret_block)
{
struct omfs_extent_entry *terminator;
- struct omfs_extent_entry *entry = &oe->e_entry;
+ struct omfs_extent_entry *entry = oe->e_entry;
struct omfs_sb_info *sbi = OMFS_SB(inode->i_sb);
u32 extent_count = be32_to_cpu(oe->e_extent_count);
u64 new_block = 0;
@@ -245,7 +245,7 @@ static int omfs_get_block(struct inode *inode, sector_t block,
extent_count = be32_to_cpu(oe->e_extent_count);
next = be64_to_cpu(oe->e_next);
- entry = &oe->e_entry;
+ entry = oe->e_entry;
if (extent_count > max_extents)
goto out_brelse;