Make H5O__fsinfo_decode() more resilient to out-of-bound reads. (#2229)

When decoding a file space info message in H5O__fsinfo_decode() make
sure each element to be decoded is still within the message. Malformed
hdf5 files may have trunkated content which does not match the
expected size. Checking this will prevent attempting to decode
unrelated data and heap overflows. So far, only free space manager
address data was checked before decoding.

This fixes CVE-2021-45830 / Bug #2228.

Signed-off-by: Egbert Eich <eich@suse.com>

Additions

Co-authored-by: Larry Knox <lrknox@hdfgroup.org>

1 files changed, 13 insertions, 3 deletions

diff --git a/src/H5Ofsinfo.c b/src/H5Ofsinfo.c
index f8455e4..4d5934d 100644
--- a/src/H5Ofsinfo.c
+++ b/src/H5Ofsinfo.c
@@ -88,6 +88,7 @@ H5FL_DEFINE_STATIC(H5O_fsinfo_t);
  *
  *-------------------------------------------------------------------------
  */
+
 static void *
 H5O__fsinfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNUSED mesg_flags,
                    unsigned H5_ATTR_UNUSED *ioflags, size_t p_size, const uint8_t *p)
@@ -112,6 +113,8 @@ H5O__fsinfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNU
         fsinfo->fs_addr[ptype - 1] = HADDR_UNDEF;
 
     /* Version of message */
+    if (p + 1 - 1 > p_end) /* one byte for version */
+        HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "ran off end of input buffer while decoding")
     vers = *p++;
 
     if (vers == H5O_FSINFO_VERSION_0) {
@@ -125,6 +128,8 @@ H5O__fsinfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNU
         fsinfo->pgend_meta_thres    = H5F_FILE_SPACE_PGEND_META_THRES;
         fsinfo->eoa_pre_fsm_fsalloc = HADDR_UNDEF;
 
+        if (p + 1 + H5F_SIZEOF_SIZE(f) - 1 > p_end) /* one byte for strategy + sizeof(f)  */
+            HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "ran off end of input buffer while decoding")
         strategy = (H5F_file_space_type_t)*p++; /* File space strategy */
         H5F_DECODE_LENGTH(f, p, threshold);     /* Free-space section threshold */
 
@@ -169,7 +174,10 @@ H5O__fsinfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNU
     else {
         HDassert(vers >= H5O_FSINFO_VERSION_1);
 
-        fsinfo->version  = vers;
+        fsinfo->version = vers;
+        /* strategy (1) + persist (1) + sizeof(f) + sizeof(f) + pgend_meta_thres (2)  + sizeofaddr(f) */
+        if (p + 1 + 1 + 2 * H5F_SIZEOF_SIZE(f) + 2 + H5F_SIZEOF_ADDR(f) - 1 > p_end)
+            HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "ran off end of input buffer while decoding")
         fsinfo->strategy = (H5F_fspace_strategy_t)*p++; /* File space strategy */
         fsinfo->persist  = *p++;                        /* Free-space persist or not */
         H5F_DECODE_LENGTH(f, p, fsinfo->threshold);     /* Free-space section threshold */
@@ -181,9 +189,11 @@ H5O__fsinfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNU
 
         /* Decode addresses of free space managers, if persisting */
         if (fsinfo->persist)
-            for (ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; ptype++)
+            for (ptype = H5F_MEM_PAGE_SUPER; ptype < H5F_MEM_PAGE_NTYPES; ptype++) {
+                if (p + H5F_SIZEOF_SIZE(f) - 1 > p_end) /* one byte for sizeof(f)  */
+                    HGOTO_ERROR(H5E_OHDR, H5E_NOSPACE, NULL, "ran off end of input buffer while decoding")
                 H5F_addr_decode(f, &p, &(fsinfo->fs_addr[ptype - 1]));
-
+            }
         fsinfo->mapped = FALSE;
     }