Quoting Bram <bram-pynzni-qr...@lists.wizbit.be>:
I decided to have a look on how to change the behaviour and wrote a
patch for it.
I don't know if this patch is desirable or acceptable but I'm
submitting it anyway.
Patch is against 0.97.3 but should apply cleanly on git master.
...
It appears the list removed the attachment so here's an inline version of it:
diff -Naur clamav-0.97.3.orig/libclamav/unzip.c
clamav-0.97.3.patched/libclamav/unzip.c
--- clamav-0.97.3.orig/libclamav/unzip.c 2011-01-10 18:48:28.000000000
+0100
+++ clamav-0.97.3.patched/libclamav/unzip.c 2011-12-21
16:53:29.000000000 +0100
@@ -56,7 +56,7 @@
return inflateInit2(a, b);
}
-static int unz(uint8_t *src, uint32_t csize, uint32_t usize, uint16_t
method, uint16_t flags, unsigned int *fu, cli_ctx *ctx, char *tmpd) {
+static int unz(uint8_t *src, uint32_t csize, uint32_t usize, uint16_t
method, uint16_t flags, unsigned int *fu, cli_ctx *ctx, char *tmpd,
fmap_t *map) {
char name[1024], obuf[BUFSIZ];
char *tempfile = name;
int of, ret=CL_CLEAN;
@@ -78,7 +78,7 @@
if(csize<usize) {
unsigned int fake = *fu + 1;
cli_dbgmsg("cli_unzip: attempting to inflate stored file with
inconsistent size\n");
- if ((ret=unz(src, csize, usize, ALG_DEFLATE, 0, &fake, ctx,
tmpd))==CL_CLEAN) {
+ if ((ret=unz(src, csize, usize, ALG_DEFLATE, 0, &fake, ctx,
tmpd, map))==CL_CLEAN) {
(*fu)++;
res=fake-(*fu);
}
@@ -134,17 +134,57 @@
memset(&strm, 0, sizeof(strm));
- *next_in = src;
*next_out = obuf;
- *avail_in = csize;
*avail_out = sizeof(obuf);
if (unz_init(&strm, -wbits)!=Z_OK) {
cli_dbgmsg("cli_unzip: zinit failed\n");
break;
}
- while(1) {
- while((res = unz_unz(&strm, Z_NO_FLUSH))==Z_OK) {};
- if(*avail_out!=sizeof(obuf)) {
+
+ int chunk_size = BUFSIZ;
+ uint32_t remaining = csize;
+
+ do {
+ /* 'read' a chunk of data */
+ if (remaining >= chunk_size) {
+ if (fmap_need_ptr_once(map, src, chunk_size)) {
+ *avail_in = chunk_size;
+ *next_in = src;
+
+ src += chunk_size;
+ remaining -= chunk_size;
+ }
+ else {
+ cli_dbgmsg("cli_unzip: fmap_need_ptr_once failed?!\n");
+ }
+ }
+ else {
+ if (remaining == 0) {
+ /* corrupted file? zlib has not detected a STREAM_END and expects
more but all input is consumed... */
+ cli_dbgmsg("cli_unzip: entire input stream used but zlib expets
more...\n");
+ res = Z_DATA_ERROR;
+ break;
+ }
+ else {
+ if (fmap_need_ptr_once(map, src, remaining)) {
+ *avail_in = remaining;
+ *next_in = src;
+
+ src += remaining;
+ remaining -= remaining;
+ }
+ else {
+ cli_dbgmsg("cli_unzip: fmap_need_ptr_once failed?!\n");
+ }
+ }
+ }
+
+ /* inflate the data chunk */
+ do {
+ *next_out = obuf;
+ *avail_out = sizeof(obuf);
+
+ res = unz_unz(&strm, Z_NO_FLUSH);
written+=sizeof(obuf)-(*avail_out);
if(ctx->engine->maxfilesize && written > ctx->engine->maxfilesize) {
cli_dbgmsg("cli_unzip: trimming output size to maxfilesize
(%lu)\n", (long unsigned int) ctx->engine->maxfilesize);
@@ -157,12 +197,9 @@
res = 100;
break;
}
- *next_out = obuf;
- *avail_out = sizeof(obuf);
- continue;
- }
- break;
- }
+ } while (*avail_out == 0);
+ } while (res != Z_DATA_ERROR && res != Z_STREAM_END && res != 100);
+
unz_end(&strm);
if (res == Z_STREAM_END) res=0;
break;
@@ -384,8 +421,7 @@
if(LH_flags & F_ENCR) {
cli_dbgmsg("cli_unzip: lh - skipping encrypted file\n");
} else {
- if(fmap_need_ptr_once(map, zip, csize))
- *ret = unz(zip, csize, usize, LH_method, LH_flags, fu, ctx, tmpd);
+ *ret = unz(zip, csize, usize, LH_method, LH_flags, fu, ctx, tmpd,
map);
}
zip+=csize;
zsize-=csize;
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