From: Eric Biggers Date: Sun, 6 Nov 2022 22:48:37 +0000 (-0800) Subject: ext4: fix leaking uninitialized memory in fast-commit journal X-Git-Tag: v6.1.8~574 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=7c1fb65e8ce85c281d2cba9c236f9edbbc4eaca6;p=platform%2Fkernel%2Flinux-starfive.git ext4: fix leaking uninitialized memory in fast-commit journal commit 594bc43b410316d70bb42aeff168837888d96810 upstream. 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: # v5.10+ Signed-off-by: Eric Biggers Link: https://lore.kernel.org/r/20221106224841.279231-4-ebiggers@kernel.org Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index 6d98f2b..bec5bc5 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);