dovecot-2.2: lib: data-stack - add vital sanity-preserving asser...

[dovecot at dovecot.org]

details:   http://hg.dovecot.org/dovecot-2.2/rev/90a8729d81c8
changeset: 17646:90a8729d81c8
user:      Phil Carmody <phil at dovecot.fi>
date:      Mon Jul 28 16:45:33 2014 +0300
description:
lib: data-stack - add vital sanity-preserving assert to t_pop
If something has re-ordered those two offsets, the following memset
will explode.

Signed-off-by: Phil Carmody <phil at dovecot.fi>

diffstat:

 src/lib/data-stack.c |  1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diffs (11 lines):

diff -r 87629dec23f1 -r 90a8729d81c8 src/lib/data-stack.c
--- a/src/lib/data-stack.c	Mon Jul 28 16:45:33 2014 +0300
+++ b/src/lib/data-stack.c	Mon Jul 28 16:45:33 2014 +0300
@@ -278,6 +278,7 @@
 		pos = current_block->size -
 			current_frame_block->block_space_used[frame_pos];
 		used_size = current_block->size - current_block->lowwater;
+		i_assert(used_size >= pos);
 		memset(STACK_BLOCK_DATA(current_block) + pos, CLEAR_CHR,
 		       used_size - pos);
 	}