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| author | zhangyi (F) <yi.zhang@huawei.com> | 2019-08-28 11:25:01 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2019-08-28 11:25:01 -0400 |
| commit | 9ba55543fc0c6bb1cf8edd63be8802d9ab7e1202 (patch) | |
| tree | b2503c97d463788e71e19a921ca0df173d4f5c21 /fs/ext4 | |
| parent | 520f897a3554b0665af1ae5d5ba286f290cecf5c (diff) | |
| download | linux-9ba55543fc0c6bb1cf8edd63be8802d9ab7e1202.tar.bz2 | |
ext4: fix integer overflow when calculating commit interval
If user specify a large enough value of "commit=" option, it may trigger
signed integer overflow which may lead to sbi->s_commit_interval becomes
a large or small value, zero in particular.
UBSAN: Undefined behaviour in ../fs/ext4/super.c:1592:31
signed integer overflow:
536870912 * 1000 cannot be represented in type 'int'
[...]
Call trace:
[...]
[<ffffff9008a2d120>] ubsan_epilogue+0x34/0x9c lib/ubsan.c:166
[<ffffff9008a2d8b8>] handle_overflow+0x228/0x280 lib/ubsan.c:197
[<ffffff9008a2d95c>] __ubsan_handle_mul_overflow+0x4c/0x68 lib/ubsan.c:218
[<ffffff90086d070c>] handle_mount_opt fs/ext4/super.c:1592 [inline]
[<ffffff90086d070c>] parse_options+0x1724/0x1a40 fs/ext4/super.c:1773
[<ffffff90086d51c4>] ext4_remount+0x2ec/0x14a0 fs/ext4/super.c:4834
[...]
Although it is not a big deal, still silence the UBSAN by limit the
input value.
Signed-off-by: zhangyi (F) <yi.zhang@huawei.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/super.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 4079605d437a..7310facffa9d 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1874,6 +1874,13 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, } else if (token == Opt_commit) { if (arg == 0) arg = JBD2_DEFAULT_MAX_COMMIT_AGE; + else if (arg > INT_MAX / HZ) { + ext4_msg(sb, KERN_ERR, + "Invalid commit interval %d, " + "must be smaller than %d", + arg, INT_MAX / HZ); + return -1; + } sbi->s_commit_interval = HZ * arg; } else if (token == Opt_debug_want_extra_isize) { sbi->s_want_extra_isize = arg; |