From: Phil Carmody <phil@dovecot.fi>
Date: Mon, 28 Jul 2014 13:45:33 +0000 (+0300)
Subject: lib: data-stack - add vital sanity-preserving assert to t_pop
X-Git-Tag: 2.2.14.rc1~224
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f9bee080651276b7baf037c3f0bd84e41a40a433;p=thirdparty%2Fdovecot%2Fcore.git

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@dovecot.fi>
---

diff --git a/src/lib/data-stack.c b/src/lib/data-stack.c
index 99926c9dc3..53e6945d56 100644
--- a/src/lib/data-stack.c
+++ b/src/lib/data-stack.c
@@ -278,6 +278,7 @@ unsigned int t_pop(void)
 		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);
 	}