commit d61d0ab573649789bf9eb909c89a1a193b2e3d10 upstream.

When mounting a filesystem image with a block size larger than the page size, nilfs2 repeatedly outputs long error messages with stack traces to the kernel log, such as the following:

getblk(): invalid block size 8192 requested logical block size: 512 ... Call Trace: dump_stack_lvl+0x92/0xd4 dump_stack+0xd/0x10 bdev_getblk+0x33a/0x354 __breadahead+0x11/0x80 nilfs_search_super_root+0xe2/0x704 [nilfs2] load_nilfs+0x72/0x504 [nilfs2] nilfs_mount+0x30f/0x518 [nilfs2] legacy_get_tree+0x1b/0x40 vfs_get_tree+0x18/0xc4 path_mount+0x786/0xa88 __ia32_sys_mount+0x147/0x1a8 __do_fast_syscall_32+0x56/0xc8 do_fast_syscall_32+0x29/0x58 do_SYSENTER_32+0x15/0x18 entry_SYSENTER_32+0x98/0xf1 ...

This overloads the system logger. And to make matters worse, it sometimes crashes the kernel with a memory access violation.

This is because the return value of the sb_set_blocksize() call, which should be checked for errors, is not checked.

The latter issue is due to out-of-buffer memory being accessed based on a large block size that caused sb_set_blocksize() to fail for buffers read with the initial minimum block size that remained unupdated in the super_block structure.

Since nilfs2 mkfs tool does not accept block sizes larger than the system page size, this has been overlooked. However, it is possible to create this situation by intentionally modifying the tool or by passing a filesystem image created on a system with a large page size to a system with a smaller page size and mounting it.

Fix this issue by inserting the expected error handling for the call to sb_set_blocksize().

Link: https://lkml.kernel.org/r/20231129141547.4726-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi konishi.ryusuke@gmail.com Tested-by: Ryusuke Konishi konishi.ryusuke@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org --- Please apply this patch to the stable trees indicated by the subject line prefix, instead of the patch I asked you to drop earlier.

In this patch, "nilfs_err()" is replaced with its equivalent since it doesn't yet exist in these kernels. With this tweak, this patch is applicable from v4.8 to v5.8. Also this patch has been tested against these three stable trees.

Thanks, Ryusuke Konishi

fs/nilfs2/the_nilfs.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index d550a564645e..c8d869bc25b0 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -688,7 +688,11 @@ int init_nilfs(struct the_nilfs *nilfs, struct super_block *sb, char *data) goto failed_sbh; } nilfs_release_super_block(nilfs); - sb_set_blocksize(sb, blocksize); + if (!sb_set_blocksize(sb, blocksize)) { + nilfs_msg(sb, KERN_ERR, "bad blocksize %d", blocksize); + err = -EINVAL; + goto out; + }

err = nilfs_load_super_block(nilfs, sb, blocksize, &sbp); if (err)