Fixed GH-2603, heap-buffer-overflow in H5O__linfo_decode (#2697)

* Fixed GH-2603, heap-buffer-overflow in H5O__linfo_decode

Verified with valgrind -v --tool=memcheck --leak-check=full h5dump POV-GH-2603
The several invalid reads shown originally are now gone.

1 files changed, 22 insertions, 6 deletions

diff --git a/src/H5Olinfo.c b/src/H5Olinfo.c
index d4ac3bb..11138df 100644
--- a/src/H5Olinfo.c
+++ b/src/H5Olinfo.c
@@ -105,11 +105,13 @@ H5FL_DEFINE_STATIC(H5O_linfo_t);
  */
 static void *
 H5O__linfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNUSED mesg_flags,
-                  unsigned H5_ATTR_UNUSED *ioflags, size_t H5_ATTR_UNUSED p_size, const uint8_t *p)
+                  unsigned H5_ATTR_UNUSED *ioflags, size_t p_size, const uint8_t *p)
 {
-    H5O_linfo_t  *linfo = NULL;     /* Link info */
-    unsigned char index_flags;      /* Flags for encoding link index info */
-    void         *ret_value = NULL; /* Return value */
+    const uint8_t *p_end = p + p_size - 1;         /* End of the p buffer */
+    H5O_linfo_t   *linfo = NULL;                   /* Link info */
+    unsigned char  index_flags;                    /* Flags for encoding link index info */
+    uint8_t        addr_size = H5F_SIZEOF_ADDR(f); /* Temp var */
+    void          *ret_value = NULL;               /* Return value */
 
     FUNC_ENTER_PACKAGE
 
@@ -117,6 +119,10 @@ H5O__linfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNUS
     HDassert(f);
     HDassert(p);
 
+    /* Check input buffer before decoding version and index flags */
+    if (H5_IS_BUFFER_OVERFLOW(p, 2, p_end))
+        HGOTO_ERROR(H5E_OHDR, H5E_OVERFLOW, NULL, "ran off end of input buffer while decoding")
+
     /* Version of message */
     if (*p++ != H5O_LINFO_VERSION)
         HGOTO_ERROR(H5E_OHDR, H5E_CANTLOAD, NULL, "bad version number for message")
@@ -136,11 +142,18 @@ H5O__linfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNUS
     linfo->nlinks = HSIZET_MAX;
 
     /* Max. link creation order value for the group, if tracked */
-    if (linfo->track_corder)
+    if (linfo->track_corder) {
+        if (H5_IS_BUFFER_OVERFLOW(p, 8, p_end))
+            HGOTO_ERROR(H5E_OHDR, H5E_OVERFLOW, NULL, "ran off end of input buffer while decoding")
         INT64DECODE(p, linfo->max_corder)
+    }
     else
         linfo->max_corder = 0;
 
+    /* Check input buffer before decoding the next two addresses */
+    if (H5_IS_BUFFER_OVERFLOW(p, addr_size + addr_size, p_end))
+        HGOTO_ERROR(H5E_OHDR, H5E_OVERFLOW, NULL, "ran off end of input buffer while decoding")
+
     /* Address of fractal heap to store "dense" links */
     H5F_addr_decode(f, &p, &(linfo->fheap_addr));
 
@@ -148,8 +161,11 @@ H5O__linfo_decode(H5F_t *f, H5O_t H5_ATTR_UNUSED *open_oh, unsigned H5_ATTR_UNUS
     H5F_addr_decode(f, &p, &(linfo->name_bt2_addr));
 
     /* Address of v2 B-tree to index creation order of links, if there is one */
-    if (linfo->index_corder)
+    if (linfo->index_corder) {
+        if (H5_IS_BUFFER_OVERFLOW(p, addr_size, p_end))
+            HGOTO_ERROR(H5E_OHDR, H5E_OVERFLOW, NULL, "ran off end of input buffer while decoding")
         H5F_addr_decode(f, &p, &(linfo->corder_bt2_addr));
+    }
     else
         linfo->corder_bt2_addr = HADDR_UNDEF;