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authorGravatar Filippo Bigarella2016-11-10 01:31:23 +0100
committerGravatar Nikias Bassen2016-11-10 01:31:23 +0100
commita4ca24c4fe316bc102b9fa52f808d206ab8cd24b (patch)
tree884d0049709a7e011a28b3e7a8c529c262de676a
parent1ae55728f427532234be85a90322e4a3c77b4074 (diff)
downloadlibplist-a4ca24c4fe316bc102b9fa52f808d206ab8cd24b.tar.gz
libplist-a4ca24c4fe316bc102b9fa52f808d206ab8cd24b.tar.bz2
bplist: Prevent out-of-bounds read in plist_from_bin() when parsing offset_table
offset_table_index is read from the file, so we have full control over it. This means we can point offset_table essentially anywhere we want, which can lead to an out-of-bounds read when it will be used later on.
-rw-r--r--src/bplist.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/src/bplist.c b/src/bplist.c
index 8447187..be82b4e 100644
--- a/src/bplist.c
+++ b/src/bplist.c
@@ -708,6 +708,7 @@ PLIST_API void plist_from_bin(const char *plist_bin, uint32_t length, plist_t *
uint64_t num_objects = 0;
uint64_t root_object = 0;
uint64_t offset_table_index = 0;
+ char *offset_table = NULL;
//first check we have enough data
if (!(length >= BPLIST_MAGIC_SIZE + BPLIST_VERSION_SIZE + BPLIST_TRL_SIZE))
@@ -727,6 +728,7 @@ PLIST_API void plist_from_bin(const char *plist_bin, uint32_t length, plist_t *
num_objects = be64dec(trailer + BPLIST_TRL_NUMOBJ_IDX);
root_object = be64dec(trailer + BPLIST_TRL_ROOTOBJ_IDX);
offset_table_index = be64dec(trailer + BPLIST_TRL_OFFTAB_IDX);
+ offset_table = (char *) (plist_bin + offset_table_index);
if (num_objects == 0)
return;
@@ -734,13 +736,19 @@ PLIST_API void plist_from_bin(const char *plist_bin, uint32_t length, plist_t *
if (root_object >= num_objects)
return;
+ if (offset_table < plist_bin || offset_table >= plist_bin + length)
+ return;
+
+ if (offset_table + num_objects * offset_size >= plist_bin + length)
+ return;
+
struct bplist_data bplist;
bplist.data = plist_bin;
bplist.size = length;
bplist.num_objects = num_objects;
bplist.dict_size = dict_size;
bplist.offset_size = offset_size;
- bplist.offset_table = (char *) (plist_bin + offset_table_index);
+ bplist.offset_table = offset_table;
bplist.level = 0;
bplist.used_indexes = (uint32_t*)malloc(sizeof(uint32_t) * num_objects);