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fs/ntfs3: validate BOOT sectors_per_clusters

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When the NTFS BOOT sectors_per_clusters field is > 0x80, it represents a
shift value.  Make sure that the shift value is not too large before using
it (NTFS max cluster size is 2MB).  Return -EVINVAL if it too large.

This prevents negative shift values and shift values that are larger than
the field size.

Prevents this UBSAN error:

 UBSAN: shift-out-of-bounds in ../fs/ntfs3/super.c:673:16
 shift exponent -192 is negative

Link: https://lkml.kernel.org/r/20220502175342.20296-1-rdunlap@infradead.org
Fixes: 82cae269cf ("fs/ntfs3: Add initialization of super block")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: syzbot+1631f09646bc214d2e76@syzkaller.appspotmail.com
Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Kari Argillander <kari.argillander@stargateuniverse.net>
Cc: Namjae Jeon <linkinjeon@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Randy Dunlap 2022-05-12 20:38:37 -07:00 committed by Andrew Morton
parent cd290a9839
commit a3b774342f
1 changed files with 7 additions and 3 deletions
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10
fs/ntfs3/super.c
View File

@ -668,9 +668,11 @@ static u32 format_size_gb(const u64 bytes, u32 *mb)
static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot)
{
return boot->sectors_per_clusters <= 0x80
? boot->sectors_per_clusters
: (1u << (0 - boot->sectors_per_clusters));
if (boot->sectors_per_clusters <= 0x80)
return boot->sectors_per_clusters;
if (boot->sectors_per_clusters >= 0xf4) /* limit shift to 2MB max */
return 1U << (0 - boot->sectors_per_clusters);
return -EINVAL;
}
/*
@ -713,6 +715,8 @@ static int ntfs_init_from_boot(struct super_block *sb, u32 sector_size,
/* cluster size: 512, 1K, 2K, 4K, ... 2M */
sct_per_clst = true_sectors_per_clst(boot);
if ((int)sct_per_clst < 0)
goto out;
if (!is_power_of_2(sct_per_clst))
goto out;