@@ -839,15 +839,23 @@ static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
{
jbd2_journal_revoke_header_t *header;
int offset, max;
+ int csum_size = 0;
+ __u32 rcount;
int record_len = 4;
header = (jbd2_journal_revoke_header_t *) bh->b_data;
offset = sizeof(jbd2_journal_revoke_header_t);
- max = be32_to_cpu(header->r_count);
+ rcount = be32_to_cpu(header->r_count);
if (!jbd2_revoke_block_csum_verify(journal, header))
return -EINVAL;
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_revoke_tail);
+ if (rcount > journal->j_blocksize - csum_size)
+ return -EINVAL;
+ max = rcount;
+
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
record_len = 8;
@@ -583,7 +583,7 @@ static void write_one_revoke_record(journal_t *journal,
{
int csum_size = 0;
struct buffer_head *descriptor;
- int offset;
+ int sz, offset;
journal_header_t *header;
/* If we are already aborting, this all becomes a noop. We
@@ -600,9 +600,14 @@ static void write_one_revoke_record(journal_t *journal,
if (jbd2_journal_has_csum_v2or3(journal))
csum_size = sizeof(struct jbd2_journal_revoke_tail);
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
+ sz = 8;
+ else
+ sz = 4;
+
/* Make sure we have a descriptor with space left for the record */
if (descriptor) {
- if (offset >= journal->j_blocksize - csum_size) {
+ if (offset + sz > journal->j_blocksize - csum_size) {
flush_descriptor(journal, descriptor, offset, write_op);
descriptor = NULL;
}
@@ -625,16 +630,13 @@ static void write_one_revoke_record(journal_t *journal,
*descriptorp = descriptor;
}
- if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT)) {
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
* ((__be64 *)(&descriptor->b_data[offset])) =
cpu_to_be64(record->blocknr);
- offset += 8;
-
- } else {
+ else
* ((__be32 *)(&descriptor->b_data[offset])) =
cpu_to_be32(record->blocknr);
- offset += 4;
- }
+ offset += sz;
*offsetp = offset;
}
This is a note to let you know that I have just added a patch titled jbd2: fix r_count overflows leading to buffer overflow in journal recovery to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt22. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 69daefc679aabaa15793bb5062d73aea8feed3c6 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" <darrick.wong@oracle.com> Date: Thu, 14 May 2015 19:11:50 -0400 Subject: jbd2: fix r_count overflows leading to buffer overflow in journal recovery commit e531d0bceb402e643a4499de40dd3fa39d8d2e43 upstream. The journal revoke block recovery code does not check r_count for sanity, which means that an evil value of r_count could result in the kernel reading off the end of the revoke table and into whatever garbage lies beyond. This could crash the kernel, so fix that. However, in testing this fix, I discovered that the code to write out the revoke tables also was not correctly checking to see if the block was full -- the current offset check is fine so long as the revoke table space size is a multiple of the record size, but this is not true when either journal_csum_v[23] are set. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- fs/jbd2/recovery.c | 10 +++++++++- fs/jbd2/revoke.c | 18 ++++++++++-------- 2 files changed, 19 insertions(+), 9 deletions(-) -- 1.9.1