[PATCH 2/4] libm/stdlib: don't read past source in nano_realloc
Keith Packard
keithp@keithp.com
Tue Aug 11 23:05:41 GMT 2020
Save the computed block size and use it to avoid reading past
the end of the source block.
Signed-off-by: Keith Packard <keithp@keithp.com>
---
newlib/libc/stdlib/nano-mallocr.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/newlib/libc/stdlib/nano-mallocr.c b/newlib/libc/stdlib/nano-mallocr.c
index 04465eb9e..cef23977e 100644
--- a/newlib/libc/stdlib/nano-mallocr.c
+++ b/newlib/libc/stdlib/nano-mallocr.c
@@ -466,6 +466,7 @@ void * nano_realloc(RARG void * ptr, malloc_size_t size)
{
void * mem;
chunk * p_to_realloc;
+ malloc_size_t old_size;
if (ptr == NULL) return nano_malloc(RCALL size);
@@ -477,12 +478,15 @@ void * nano_realloc(RARG void * ptr, malloc_size_t size)
/* TODO: There is chance to shrink the chunk if newly requested
* size is much small */
- if (nano_malloc_usable_size(RCALL ptr) >= size)
+ old_size = nano_malloc_usable_size(RCALL ptr);
+ if (old_size >= size)
return ptr;
mem = nano_malloc(RCALL size);
if (mem != NULL)
{
+ if (size > old_size)
+ size = old_size;
memcpy(mem, ptr, size);
nano_free(RCALL ptr);
}
--
2.28.0
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