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| author | Theodore Ts'o <tytso@mit.edu> | 2018-09-01 19:45:04 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-29 13:06:06 +0300 |
| commit | 779af00b3fa38d040a4798afdb2c57cc64ba346e (patch) | |
| tree | b1fc41b567f8f0ac5ea71d9e39cb6a693974e863 /fs/ext4/inode.c | |
| parent | 3f9eafe8772f9a86cab2e431a44bce775f6b7ba5 (diff) | |
| download | linux-779af00b3fa38d040a4798afdb2c57cc64ba346e.tar.xz | |
ext4: avoid arithemetic overflow that can trigger a BUG
commit bcd8e91f98c156f4b1ebcfacae675f9cfd962441 upstream.
A maliciously crafted file system can cause an overflow when the
results of a 64-bit calculation is stored into a 32-bit length
parameter.
https://bugzilla.kernel.org/show_bug.cgi?id=200623
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reported-by: Wen Xu <wen.xu@gatech.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/ext4/inode.c')
| -rw-r--r-- | fs/ext4/inode.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index f9baa59de0e2..9808df52ceca 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3407,11 +3407,16 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, { struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); unsigned int blkbits = inode->i_blkbits; - unsigned long first_block = offset >> blkbits; - unsigned long last_block = (offset + length - 1) >> blkbits; + unsigned long first_block, last_block; struct ext4_map_blocks map; int ret; + if ((offset >> blkbits) > EXT4_MAX_LOGICAL_BLOCK) + return -EINVAL; + first_block = offset >> blkbits; + last_block = min_t(loff_t, (offset + length - 1) >> blkbits, + EXT4_MAX_LOGICAL_BLOCK); + if (WARN_ON_ONCE(ext4_has_inline_data(inode))) return -ERANGE; |