6.12-stable review patch. If anyone has any objections, please let me know.
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From: Nikita Zhandarovich n.zhandarovich@fintech.ru
commit 6438ef381c183444f7f9d1de18f22661cba1e946 upstream.
Since nilfs_bmap_lookup_contig() in nilfs_fiemap() calculates its result by being prepared to go through potentially maxblocks == INT_MAX blocks, the value in n may experience an overflow caused by left shift of blkbits.
While it is extremely unlikely to occur, play it safe and cast right hand expression to wider type to mitigate the issue.
Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.
Link: https://lkml.kernel.org/r/20250124222133.5323-1-konishi.ryusuke@gmail.com Fixes: 622daaff0a89 ("nilfs2: fiemap support") Signed-off-by: Nikita Zhandarovich n.zhandarovich@fintech.ru Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/nilfs2/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
--- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -1219,7 +1219,7 @@ int nilfs_fiemap(struct inode *inode, st if (size) { if (phys && blkphy << blkbits == phys + size) { /* The current extent goes on */ - size += n << blkbits; + size += (u64)n << blkbits; } else { /* Terminate the current extent */ ret = fiemap_fill_next_extent( @@ -1232,14 +1232,14 @@ int nilfs_fiemap(struct inode *inode, st flags = FIEMAP_EXTENT_MERGED; logical = blkoff << blkbits; phys = blkphy << blkbits; - size = n << blkbits; + size = (u64)n << blkbits; } } else { /* Start a new extent */ flags = FIEMAP_EXTENT_MERGED; logical = blkoff << blkbits; phys = blkphy << blkbits; - size = n << blkbits; + size = (u64)n << blkbits; } blkoff += n; }