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Fix scan error when image fuzzy hash fails #618

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Merged
val-ms merged 1 commit into from
Jul 19, 2022
Merged

Fix scan error when image fuzzy hash fails #618

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3 changes: 2 additions & 1 deletion libclamav/matcher.c
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Original file line number Diff line number Diff line change
Expand Up @@ -200,7 +200,8 @@ static inline cl_error_t matcher_run(const struct cli_matcher *root,
case CL_TYPE_JPEG:
case CL_TYPE_PNG:
case CL_TYPE_GRAPHICS: {
if (!fuzzy_hash_check(root->fuzzy_hashmap, mdata, ctx->recursion_stack[ctx->recursion_level].image_fuzzy_hash)) {
if (ctx->recursion_stack[ctx->recursion_level].calculated_image_fuzzy_hash &&
!fuzzy_hash_check(root->fuzzy_hashmap, mdata, ctx->recursion_stack[ctx->recursion_level].image_fuzzy_hash)) {
cli_errmsg("Unexpected error when checking for fuzzy hash matches.\n");
return CL_ERROR;
}
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1 change: 1 addition & 0 deletions libclamav/others.h
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Expand Up @@ -187,6 +187,7 @@ typedef struct recursion_level_tag {
uint32_t recursion_level_buffer_fmap; /* Which fmap layer in this buffer. */
bool is_normalized_layer; /* Indicates that the layer should be skipped when checking container and intermediate types. */
image_fuzzy_hash_t image_fuzzy_hash; /* Used for image/graphics files to store a fuzzy hash. */
bool calculated_image_fuzzy_hash; /* Used for image/graphics files to store a fuzzy hash. */
} recursion_level_t;

/* internal clamav context */
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56 changes: 43 additions & 13 deletions libclamav/scanners.c
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Expand Up @@ -4105,7 +4105,8 @@ static cl_error_t calculate_fuzzy_image_hash(cli_ctx *ctx, cli_file_t type)
(void)cli_jsonstr(header, "Hash", hashstr);
}

ctx->recursion_stack[ctx->recursion_level].image_fuzzy_hash = hash;
ctx->recursion_stack[ctx->recursion_level].image_fuzzy_hash = hash;
ctx->recursion_stack[ctx->recursion_level].calculated_image_fuzzy_hash = true;

status = CL_SUCCESS;

Expand Down Expand Up @@ -4652,47 +4653,76 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
* Note: JPEG 2000 is a very different format from JPEG, JPEG/JFIF, JPEG/Exif, JPEG/SPIFF (1994, 1997)
* JPEG 2000 is not handled by cli_scanjpeg or cli_parsejpeg.
*/
ret = calculate_fuzzy_image_hash(ctx, type);

// It's okay if it fails to calculate the fuzzy hash.
(void)calculate_fuzzy_image_hash(ctx, type);

break;
}

case CL_TYPE_GIF: {
ret = calculate_fuzzy_image_hash(ctx, type);
if (SCAN_HEURISTICS && SCAN_HEURISTIC_BROKEN_MEDIA && (DCONF_OTHER & OTHER_CONF_GIF)) {
ret = cli_parsegif(ctx);
}

if (CL_SUCCESS != ret) {
// do not calculate the fuzzy image hash if parsing failed, or a heuristic alert occured.
break;
}

if (SCAN_HEURISTICS && SCAN_HEURISTIC_BROKEN_MEDIA && (DCONF_OTHER & OTHER_CONF_GIF))
ret = cli_parsegif(ctx);
// It's okay if it fails to calculate the fuzzy hash.
(void)calculate_fuzzy_image_hash(ctx, type);

break;
}

case CL_TYPE_PNG: {
ret = calculate_fuzzy_image_hash(ctx, type);
if (SCAN_HEURISTICS && (DCONF_OTHER & OTHER_CONF_PNG)) {
ret = cli_parsepng(ctx); /* PNG parser detects a couple CVE's as well as Broken.Media */
}

if (CL_SUCCESS != ret) {
// do not calculate the fuzzy image hash if parsing failed, or a heuristic alert occured.
break;
}

if (SCAN_HEURISTICS && (DCONF_OTHER & OTHER_CONF_PNG))
ret = cli_parsepng(ctx); /* PNG parser detects a couple CVE's as well as Broken.Media */
// It's okay if it fails to calculate the fuzzy hash.
(void)calculate_fuzzy_image_hash(ctx, type);

break;
}

case CL_TYPE_JPEG: {
ret = calculate_fuzzy_image_hash(ctx, type);
if (SCAN_HEURISTICS && (DCONF_OTHER & OTHER_CONF_JPEG)) {
ret = cli_parsejpeg(ctx); /* JPG parser detects MS04-028 exploits as well as Broken.Media */
}

if (CL_SUCCESS != ret) {
// do not calculate the fuzzy image hash if parsing failed, or a heuristic alert occured.
break;
}

if (SCAN_HEURISTICS && (DCONF_OTHER & OTHER_CONF_JPEG))
ret = cli_parsejpeg(ctx); /* JPG parser detects MS04-028 exploits as well as Broken.Media */
// It's okay if it fails to calculate the fuzzy hash.
(void)calculate_fuzzy_image_hash(ctx, type);

break;
}

case CL_TYPE_TIFF:
if (SCAN_HEURISTICS && SCAN_HEURISTIC_BROKEN_MEDIA && (DCONF_OTHER & OTHER_CONF_TIFF) && ret != CL_VIRUS)
case CL_TYPE_TIFF: {
if (SCAN_HEURISTICS && SCAN_HEURISTIC_BROKEN_MEDIA && (DCONF_OTHER & OTHER_CONF_TIFF) && ret != CL_VIRUS) {
ret = cli_parsetiff(ctx);
}

if (CL_SUCCESS != ret) {
// do not calculate the fuzzy image hash if parsing failed, or a heuristic alert occured.
break;
}

// It's okay if it fails to calculate the fuzzy hash.
(void)calculate_fuzzy_image_hash(ctx, type);

break;
}

case CL_TYPE_CRYPTFF:
if (DCONF_OTHER & OTHER_CONF_CRYPTFF)
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