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Add buffer overflow detection #5884

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Merged
merged 4 commits into from
Oct 15, 2025
Merged

Add buffer overflow detection #5884

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d5f05f3
Harden H5C__decode_cache_image_header() by adding buffer overflow checks
bmribler Sep 27, 2025
df86e9d
Committing clang-format changes
github-actions[bot] Sep 27, 2025
9e9f28d
Fix typos
bmribler Sep 28, 2025
17b13b0
Code improvement
bmribler Oct 10, 2025
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21 changes: 15 additions & 6 deletions src/H5Cimage.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1277,7 +1277,8 @@ H5C__decode_cache_image_header(const H5F_t *f, H5C_t *cache_ptr, const uint8_t *
size_t actual_header_len;
size_t expected_header_len;
const uint8_t *p;
herr_t ret_value = SUCCEED; /* Return value */
const uint8_t *p_end = *buf + buf_size - 1; /* End of the p buffer */
herr_t ret_value = SUCCEED; /* Return value */

FUNC_ENTER_PACKAGE

Expand All @@ -1290,7 +1291,7 @@ H5C__decode_cache_image_header(const H5F_t *f, H5C_t *cache_ptr, const uint8_t *
p = *buf;

/* Ensure buffer has enough data for signature comparison */
if (H5_IS_BUFFER_OVERFLOW(p, H5C__MDCI_BLOCK_SIGNATURE_LEN, *buf + buf_size - 1))
if (H5_IS_BUFFER_OVERFLOW(p, H5C__MDCI_BLOCK_SIGNATURE_LEN, p_end))
HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "Insufficient buffer size for signature");

/* Check signature */
Expand All @@ -1299,25 +1300,33 @@ H5C__decode_cache_image_header(const H5F_t *f, H5C_t *cache_ptr, const uint8_t *
p += H5C__MDCI_BLOCK_SIGNATURE_LEN;

/* Check version */
if (H5_IS_BUFFER_OVERFLOW(p, 1, p_end))
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The buffer overflow check above if (H5_IS_BUFFER_OVERFLOW(p, H5C__MDCI_BLOCK_SIGNATURE_LEN, *buf + buf_size - 1)) should probably be updated to make use of p_end instead for consistency.

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@jhendersonHDF I made the change. Thanks!

HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
version = *p++;
if (version != (uint8_t)H5C__MDCI_BLOCK_VERSION_0)
HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "Bad metadata cache image version");

/* Decode flags */
if (H5_IS_BUFFER_OVERFLOW(p, 1, p_end))
HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
flags = *p++;
if (flags & H5C__MDCI_HEADER_HAVE_RESIZE_STATUS)
have_resize_status = true;
if (have_resize_status)
HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "MDC resize status not yet supported");

/* Read image data length */
if (H5_IS_BUFFER_OVERFLOW(p, H5F_sizeof_size(f), p_end))
HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
H5F_DECODE_LENGTH(f, p, cache_ptr->image_data_len);

/* For now -- will become <= eventually */
if (cache_ptr->image_data_len != cache_ptr->image_len)
HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "Bad metadata cache image data length");

/* Read num entries */
if (H5_IS_BUFFER_OVERFLOW(p, 4, p_end))
HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "ran off end of input buffer while decoding");
UINT32DECODE(p, cache_ptr->num_entries_in_image);
if (cache_ptr->num_entries_in_image == 0)
HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "Bad metadata cache entry count");
Expand Down Expand Up @@ -2392,18 +2401,18 @@ H5C__reconstruct_cache_contents(H5F_t *f, H5C_t *cache_ptr)
assert(cache_ptr->image_len > 0);

/* Decode metadata cache image header */
p = (uint8_t *)cache_ptr->image_buffer;
image_len = cache_ptr->image_len;
if (H5C__decode_cache_image_header(f, cache_ptr, &p, image_len + 1) < 0)
p = (uint8_t *)cache_ptr->image_buffer;
if (H5C__decode_cache_image_header(f, cache_ptr, &p, cache_ptr->image_len + 1) < 0)
HGOTO_ERROR(H5E_CACHE, H5E_CANTDECODE, FAIL, "cache image header decode failed");
assert((size_t)(p - (uint8_t *)cache_ptr->image_buffer) < image_len);
assert((size_t)(p - (uint8_t *)cache_ptr->image_buffer) < cache_ptr->image_len);

/* The image_data_len and # of entries should be defined now */
assert(cache_ptr->image_data_len > 0);
assert(cache_ptr->image_data_len <= cache_ptr->image_len);
assert(cache_ptr->num_entries_in_image > 0);

/* Reconstruct entries in image */
image_len = cache_ptr->image_len;
for (u = 0; u < cache_ptr->num_entries_in_image; u++) {
/* Create the prefetched entry described by the ith
* entry in cache_ptr->image_entrise.
Expand Down
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