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Defer or avoid file MD5 calculation when cache is disabled #1167

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merged 2 commits into from
May 6, 2024
Merged

Defer or avoid file MD5 calculation when cache is disabled #1167

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fb305a7
Defer or avoid file MD5 calculation when cache is disabled
antchan2 Nov 19, 2022
25dc1e9
Fix bug when collect-metadata is enabled and caching is disabled
micahsnyder Apr 19, 2024
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5 changes: 0 additions & 5 deletions libclamav/cache.c
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Original file line number Diff line number Diff line change
Expand Up @@ -752,11 +752,6 @@ cl_error_t clean_cache_check(unsigned char *md5, size_t size, cli_ctx *ctx)
return CL_VIRUS;
}

if (ctx->engine->engine_options & ENGINE_OPTIONS_DISABLE_CACHE) {
cli_dbgmsg("clean_cache_check: Caching disabled. Returning CL_VIRUS.\n");
return CL_VIRUS;
}

ret = cache_lookup_hash(md5, size, ctx->engine->cache, ctx->recursion_level);
cli_dbgmsg("clean_cache_check: %02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x is %s\n", md5[0], md5[1], md5[2], md5[3], md5[4], md5[5], md5[6], md5[7], md5[8], md5[9], md5[10], md5[11], md5[12], md5[13], md5[14], md5[15], (ret == CL_VIRUS) ? "negative" : "positive");
return ret;
Expand Down
42 changes: 24 additions & 18 deletions libclamav/scanners.c
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Original file line number Diff line number Diff line change
Expand Up @@ -4213,7 +4213,8 @@ static inline bool result_should_goto_done(cli_ctx *ctx, cl_error_t result_in, c
cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
{
cl_error_t ret = CL_CLEAN;
cl_error_t cache_check_result;
cl_error_t cache_check_result = CL_VIRUS;
bool cache_enabled = true;
cl_error_t verdict_at_this_level;
cli_file_t dettype = 0;
uint8_t typercg = 1;
Expand Down Expand Up @@ -4295,6 +4296,10 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
typercg = 0;
}

if (ctx->engine->engine_options & ENGINE_OPTIONS_DISABLE_CACHE) {
cache_enabled = false;
}

/*
* Perform file typing from the start of the file.
*/
Expand Down Expand Up @@ -4398,17 +4403,19 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
}

/*
* Get the maphash
* Get the maphash, if necessary
*/
if (CL_SUCCESS != fmap_get_hash(ctx->fmap, &hash, CLI_HASH_MD5)) {
cli_dbgmsg("cli_magic_scan: Failed to get a hash for the current fmap.\n");
if (cache_enabled || (SCAN_COLLECT_METADATA)) {
if (CL_SUCCESS != fmap_get_hash(ctx->fmap, &hash, CLI_HASH_MD5)) {
cli_dbgmsg("cli_magic_scan: Failed to get a hash for the current fmap.\n");

// It may be that the file was truncated between the time we started the scan and the time we got the hash.
// Not a reason to print an error message.
ret = CL_SUCCESS;
goto done;
// It may be that the file was truncated between the time we started the scan and the time we got the hash.
// Not a reason to print an error message.
ret = CL_SUCCESS;
goto done;
}
hashed_size = ctx->fmap->len;
}
hashed_size = ctx->fmap->len;

ret = dispatch_file_inspection_callback(ctx->engine->cb_file_inspection, ctx, filetype);
if (CL_CLEAN != ret) {
Expand All @@ -4423,9 +4430,11 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
/*
* Check if we've already scanned this file before.
*/
perf_start(ctx, PERFT_CACHE);
cache_check_result = clean_cache_check(hash, hashed_size, ctx);
perf_stop(ctx, PERFT_CACHE);
if (cache_enabled) {
perf_start(ctx, PERFT_CACHE);
cache_check_result = clean_cache_check(hash, hashed_size, ctx);
perf_stop(ctx, PERFT_CACHE);
}

if (SCAN_COLLECT_METADATA) {
char hashstr[CLI_HASHLEN_MD5 * 2 + 1];
Expand All @@ -4434,16 +4443,13 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
hash[8], hash[9], hash[10], hash[11], hash[12], hash[13], hash[14], hash[15]);

ret = cli_jsonstr(ctx->wrkproperty, "FileMD5", hashstr);
if (ctx->engine->engine_options & ENGINE_OPTIONS_DISABLE_CACHE) {
memset(hash, 0, CLI_HASHLEN_MD5);
}
if (ret != CL_SUCCESS) {
cli_dbgmsg("cli_magic_scan: returning %d %s (no post, no cache)\n", ret, __AT__);
goto early_ret;
}
}

if (cache_check_result != CL_VIRUS) {
if (cache_enabled && (cache_check_result != CL_VIRUS)) {
cli_dbgmsg("cli_magic_scan: returning %d %s (no post, no cache)\n", ret, __AT__);
ret = CL_SUCCESS;
goto early_ret;
Expand Down Expand Up @@ -4489,7 +4495,7 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)
* If self protection mechanism enabled, do the scanraw() scan first
* before extracting with a file type parser.
*/
ret = scanraw(ctx, type, 0, &dettype, (ctx->engine->engine_options & ENGINE_OPTIONS_DISABLE_CACHE) ? NULL : hash);
ret = scanraw(ctx, type, 0, &dettype, hash);

// Evaluate the result from the scan to see if it end the scan of this layer early,
// and to decid if we should propagate an error or not.
Expand Down Expand Up @@ -4926,7 +4932,7 @@ cl_error_t cli_magic_scan(cli_ctx *ctx, cli_file_t type)

/* CL_TYPE_HTML: raw HTML files are not scanned, unless safety measure activated via DCONF */
if (type != CL_TYPE_IGNORED && (type != CL_TYPE_HTML || !(SCAN_PARSE_HTML) || !(DCONF_DOC & DOC_CONF_HTML_SKIPRAW)) && !ctx->engine->sdb) {
ret = scanraw(ctx, type, typercg, &dettype, (ctx->engine->engine_options & ENGINE_OPTIONS_DISABLE_CACHE) ? NULL : hash);
ret = scanraw(ctx, type, typercg, &dettype, hash);

// Evaluate the result from the scan to see if it end the scan of this layer early,
// and to decid if we should propagate an error or not.
Expand Down
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