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[GNUnet-SVN] [libmicrohttpd] 02/02: memorypool: reallocate: more checks
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gnunet |
Subject: |
[GNUnet-SVN] [libmicrohttpd] 02/02: memorypool: reallocate: more checks for value wrap, small optimization |
Date: |
Thu, 13 Jun 2019 18:18:46 +0200 |
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karlson2k pushed a commit to branch master
in repository libmicrohttpd.
commit d12ed49fd33d991639512ee7637bfc644da3f123
Author: Evgeny Grin (Karlson2k) <address@hidden>
AuthorDate: Thu Jun 13 19:03:27 2019 +0300
memorypool: reallocate: more checks for value wrap, small optimization
---
src/microhttpd/memorypool.c | 32 ++++++++++++++++++--------------
1 file changed, 18 insertions(+), 14 deletions(-)
diff --git a/src/microhttpd/memorypool.c b/src/microhttpd/memorypool.c
index 5f532b83..3770b8c3 100644
--- a/src/microhttpd/memorypool.c
+++ b/src/microhttpd/memorypool.c
@@ -267,29 +267,33 @@ MHD_pool_reallocate (struct MemoryPool *pool,
/* Blocks "from the end" must not be reallocated */
mhd_assert (old == NULL || pool->memory + pool->pos > (uint8_t*)old);
- if (new_size + 2 * ALIGN_SIZE < new_size)
- return NULL; /* Value wrap, too large new_size. */
-
if (0 != old_size)
- { /* Need to relocate data */
+ { /* Need to save some data */
const size_t old_offset = (uint8_t*)old - pool->memory;
-
+ /* Try resizing in-place */
if (pool->pos == ROUND_TO_ALIGN (old_offset + old_size))
{ /* "old" block is the last allocated block */
const size_t new_apos = ROUND_TO_ALIGN (old_offset + new_size);
- if (new_apos > pool->end)
- return NULL; /* No space */
-
- pool->pos = new_apos;
- /* Zero-out unused part if shrinking */
if (old_size > new_size)
- memset ((uint8_t*)old + new_size, 0, old_size - new_size);
+ { /* Shrinking in-place, zero-out freed part */
+ memset ((uint8_t*)old + new_size, 0, old_size - new_size);
+ }
+ else
+ { /* Grow in-place, check for enough space. */
+ if ( (new_apos > pool->end) ||
+ (new_apos < pool->pos) ) /* Value wrap */
+ return NULL; /* No space */
+ }
+ /* Resized in-place */
+ pool->pos = new_apos;
return old;
}
}
/* Need to allocate new block */
asize = ROUND_TO_ALIGN (new_size);
- if (asize > pool->end - pool->pos)
+ if ( ( (0 == asize) &&
+ (0 != new_size) ) || /* Value wrap, too large new_size. */
+ (asize > pool->end - pool->pos) )
return NULL; /* No space */
new_blc = pool->memory + pool->pos;
@@ -297,9 +301,9 @@ MHD_pool_reallocate (struct MemoryPool *pool,
if (0 != old_size)
{
- /* Move data no new block, old block remains allocated */
+ /* Move data to new block, old block remains allocated */
memcpy (new_blc, old, old_size);
- /* Zero-out old block */
+ /* Zero-out freed old block */
memset (old, 0, old_size);
}
return new_blc;
--
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