[svn-r22070] Purpose: Fix rare corruption bug

Description:
When using the new object header format and adding an attribute with a size near
64K, it was possible for file corruption to occur.  This happened only if the
first object header chunk was smaller than 256 bytes and then grew to larger
than 64K after the attribute was added.

Tested: ostrich, jam, koala (h5committest), durandal

2 files changed, 29 insertions, 20 deletions

diff --git a/src/H5Oalloc.c b/src/H5Oalloc.c
index a21c2b8..dfc844d 100644
--- a/src/H5Oalloc.c
+++ b/src/H5Oalloc.c
@@ -559,26 +559,27 @@ H5O_alloc_extend_chunk(H5F_t *f, hid_t dxpl_id, H5O_t *oh, unsigned chunkno,
     /* Check for changing the chunk #0 data size enough to need adjusting the flags */
     if(oh->version > H5O_VERSION_1 && chunkno == 0) {
         uint64_t chunk0_size;           /* Size of chunk 0's data */
+        size_t   orig_prfx_size = (size_t)1 << (oh->flags & H5O_HDR_CHUNK0_SIZE); /* Original prefix size */
 
         HDassert(oh->chunk[0].size >= (size_t)H5O_SIZEOF_HDR(oh));
         chunk0_size = oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh);
 
-        /* Check for moving from a 1-byte to a 2-byte size encoding */
-        if(chunk0_size <= 255 && (chunk0_size + delta) > 255) {
-            extra_prfx_size = 1;
-            new_size_flags = H5O_HDR_CHUNK0_2;
+        /* Check for moving to a 8-byte size encoding */
+        if(orig_prfx_size < 8 && (chunk0_size + delta) > 4294967295) {
+            extra_prfx_size = 8 - orig_prfx_size;
+            new_size_flags = H5O_HDR_CHUNK0_8;
             adjust_size_flags = TRUE;
         } /* end if */
-        /* Check for moving from a 2-byte to a 4-byte size encoding */
-        else if(chunk0_size <= 65535 && (chunk0_size + delta) > 65535) {
-            extra_prfx_size = 2;
+        /* Check for moving to a 4-byte size encoding */
+        else if(orig_prfx_size < 4 && (chunk0_size + delta) > 65535) {
+            extra_prfx_size = 4 - orig_prfx_size;
             new_size_flags = H5O_HDR_CHUNK0_4;
             adjust_size_flags = TRUE;
         } /* end if */
-        /* Check for moving from a 4-byte to a 8-byte size encoding */
-        else if(chunk0_size <= 4294967295 && (chunk0_size + delta) > 4294967295) {
-            extra_prfx_size = 4;
-            new_size_flags = H5O_HDR_CHUNK0_8;
+        /* Check for moving to a 2-byte size encoding */
+        else if(orig_prfx_size < 2 && (chunk0_size + delta) > 255) {
+            extra_prfx_size = 2 - orig_prfx_size;
+            new_size_flags = H5O_HDR_CHUNK0_2;
             adjust_size_flags = TRUE;
         } /* end if */
     } /* end if */
diff --git a/src/H5Odbg.c b/src/H5Odbg.c
index bd30b90..ce8b870 100644
--- a/src/H5Odbg.c
+++ b/src/H5Odbg.c
@@ -106,7 +106,7 @@ H5O_assert(const H5O_t *oh)
 
     /* Initialize the tracking variables */
     hdr_size = 0;
-    meta_space = H5O_SIZEOF_HDR(oh) + (H5O_SIZEOF_CHKHDR_OH(oh) * (oh->nchunks - 1));
+    meta_space = (size_t)H5O_SIZEOF_HDR(oh) + (size_t)(H5O_SIZEOF_CHKHDR_OH(oh) * (oh->nchunks - 1));
     mesg_space = 0;
     free_space = 0;
 
@@ -140,7 +140,7 @@ H5O_assert(const H5O_t *oh)
 
     /* Check for correct chunk #0 size flags */
     if(oh->version > H5O_VERSION_1) {
-        uint64_t chunk0_size = oh->chunk[0].size - H5O_SIZEOF_HDR(oh);
+        uint64_t chunk0_size = oh->chunk[0].size - (size_t)H5O_SIZEOF_HDR(oh);
 
         if(chunk0_size <= 255)
             HDassert((oh->flags & H5O_HDR_CHUNK0_SIZE) == H5O_HDR_CHUNK0_1);
@@ -154,9 +154,15 @@ H5O_assert(const H5O_t *oh)
 
     /* Loop over all messages in object header */
     for(u = 0, curr_msg = &oh->mesg[0]; u < oh->nmesgs; u++, curr_msg++) {
+        uint8_t *curr_hdr;      /* Start of current message header */
+        size_t  curr_tot_size;  /* Total size of current message (including header) */
+
+        curr_hdr = curr_msg->raw - H5O_SIZEOF_MSGHDR_OH(oh);
+        curr_tot_size = curr_msg->raw_size + (size_t)H5O_SIZEOF_MSGHDR_OH(oh);
+
         /* Accumulate information, based on the type of message */
 	if(H5O_NULL_ID == curr_msg->type->id)
-            free_space += H5O_SIZEOF_MSGHDR_OH(oh) + curr_msg->raw_size;
+            free_space += curr_tot_size;
         else if(H5O_CONT_ID == curr_msg->type->id) {
             H5O_cont_t *cont = (H5O_cont_t *)curr_msg->native;
             hbool_t found_chunk = FALSE;        /* Found a chunk that matches */
@@ -175,10 +181,10 @@ H5O_assert(const H5O_t *oh)
             } /* end for */
             HDassert(found_chunk);
 
-            meta_space += H5O_SIZEOF_MSGHDR_OH(oh) + curr_msg->raw_size;
+            meta_space += curr_tot_size;
         } /* end if */
         else {
-            meta_space += H5O_SIZEOF_MSGHDR_OH(oh);
+            meta_space += (size_t)H5O_SIZEOF_MSGHDR_OH(oh);
             mesg_space += curr_msg->raw_size;
         } /* end else */
 
@@ -190,17 +196,19 @@ H5O_assert(const H5O_t *oh)
             HDassert(oh->chunk[curr_msg->chunkno].gap == 0);
 
         /* Make certain that the message is completely in a chunk message area */
-        HDassert(curr_msg->raw_size <= (oh->chunk[curr_msg->chunkno].size) - (H5O_SIZEOF_CHKSUM_OH(oh) + oh->chunk[curr_msg->chunkno].gap));
+        HDassert(curr_tot_size <= (oh->chunk[curr_msg->chunkno].size) - (H5O_SIZEOF_CHKSUM_OH(oh) + oh->chunk[curr_msg->chunkno].gap));
         if(curr_msg->chunkno == 0)
-            HDassert(curr_msg->raw >= oh->chunk[curr_msg->chunkno].image + (H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
+            HDassert(curr_hdr >= oh->chunk[curr_msg->chunkno].image + (H5O_SIZEOF_HDR(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
         else
-            HDassert(curr_msg->raw >= oh->chunk[curr_msg->chunkno].image + (H5O_SIZEOF_CHKHDR_OH(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
+            HDassert(curr_hdr >= oh->chunk[curr_msg->chunkno].image + (H5O_SIZEOF_CHKHDR_OH(oh) - H5O_SIZEOF_CHKSUM_OH(oh)));
         HDassert(curr_msg->raw + curr_msg->raw_size <= (oh->chunk[curr_msg->chunkno].image + oh->chunk[curr_msg->chunkno].size) - (H5O_SIZEOF_CHKSUM_OH(oh) + oh->chunk[curr_msg->chunkno].gap));
 
         /* Make certain that no other messages overlap this message */
         for(v = 0, tmp_msg = &oh->mesg[0]; v < oh->nmesgs; v++, tmp_msg++) {
             if(u != v)
-                HDassert(!(tmp_msg->raw >= curr_msg->raw && tmp_msg->raw < (curr_msg->raw + curr_msg->raw_size)));
+                HDassert(!((tmp_msg->raw - H5O_SIZEOF_MSGHDR_OH(oh)) >= curr_hdr
+                        && (tmp_msg->raw - H5O_SIZEOF_MSGHDR_OH(oh))
+                        < (curr_hdr + curr_tot_size)));
         } /* end for */
     } /* end for */