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| author | Eric Biggers <ebiggers@google.com> | 2022-11-07 01:48:37 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2022-12-09 05:49:24 +0300 |
| commit | 594bc43b410316d70bb42aeff168837888d96810 (patch) | |
| tree | 9caa9c31c761376a214d967845948c65525826a8 /fs/ext4 | |
| parent | 4c0d5778385cb3618ff26a561ce41de2b7d9de70 (diff) | |
| download | linux-594bc43b410316d70bb42aeff168837888d96810.tar.xz | |
ext4: fix leaking uninitialized memory in fast-commit journal
When space at the end of fast-commit journal blocks is unused, make sure
to zero it out so that uninitialized memory is not leaked to disk.
Fixes: aa75f4d3daae ("ext4: main fast-commit commit path")
Cc: <stable@vger.kernel.org> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20221106224841.279231-4-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/fast_commit.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index da0c8228cf9c..1e8be0554239 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -737,6 +737,9 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc) *crc = ext4_chksum(sbi, *crc, tl, EXT4_FC_TAG_BASE_LEN); if (pad_len > 0) ext4_fc_memzero(sb, tl + 1, pad_len, crc); + /* Don't leak uninitialized memory in the unused last byte. */ + *((u8 *)(tl + 1) + pad_len) = 0; + ext4_fc_submit_bh(sb, false); ret = jbd2_fc_get_buf(EXT4_SB(sb)->s_journal, &bh); @@ -793,6 +796,8 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc) dst += sizeof(tail.fc_tid); tail.fc_crc = cpu_to_le32(crc); ext4_fc_memcpy(sb, dst, &tail.fc_crc, sizeof(tail.fc_crc), NULL); + dst += sizeof(tail.fc_crc); + memset(dst, 0, bsize - off); /* Don't leak uninitialized memory. */ ext4_fc_submit_bh(sb, true); |