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| author | Jan Kara <jack@suse.cz> | 2023-03-01 11:59:39 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-05-24 17:32:36 +0100 |
| commit | e6f4fb28890c1361e0db9eb1adee3fc04e7fe7f5 (patch) | |
| tree | 7974772024abb529ac859b6abf73b6b5586eda8e | |
| parent | f8a6c53ff1d91acd5a20eb627edbffd816eb9a4e (diff) | |
| download | linux-e6f4fb28890c1361e0db9eb1adee3fc04e7fe7f5.tar.gz | |
ext2: Check block size validity during mount
[ Upstream commit 62aeb94433fcec80241754b70d0d1836d5926b0a ] Check that log of block size stored in the superblock has sensible value. Otherwise the shift computing the block size can overflow leading to undefined behavior. Reported-by: syzbot+4fec412f59eba8c01b77@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | fs/ext2/ext2.h | 1 | ||||
| -rw-r--r-- | fs/ext2/super.c | 7 |
2 files changed, 8 insertions, 0 deletions
diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h index 28de11a22e5f..dc5dcb78bc27 100644 --- a/fs/ext2/ext2.h +++ b/fs/ext2/ext2.h @@ -180,6 +180,7 @@ static inline struct ext2_sb_info *EXT2_SB(struct super_block *sb) #define EXT2_MIN_BLOCK_SIZE 1024 #define EXT2_MAX_BLOCK_SIZE 4096 #define EXT2_MIN_BLOCK_LOG_SIZE 10 +#define EXT2_MAX_BLOCK_LOG_SIZE 16 #define EXT2_BLOCK_SIZE(s) ((s)->s_blocksize) #define EXT2_ADDR_PER_BLOCK(s) (EXT2_BLOCK_SIZE(s) / sizeof (__u32)) #define EXT2_BLOCK_SIZE_BITS(s) ((s)->s_blocksize_bits) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 03f2af98b1b4..3feea4b31fa7 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -945,6 +945,13 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) goto failed_mount; } + if (le32_to_cpu(es->s_log_block_size) > + (EXT2_MAX_BLOCK_LOG_SIZE - BLOCK_SIZE_BITS)) { + ext2_msg(sb, KERN_ERR, + "Invalid log block size: %u", + le32_to_cpu(es->s_log_block_size)); + goto failed_mount; + } blocksize = BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size); if (test_opt(sb, DAX)) { |