[Asterisk-code-review] res_http_media_cache: Do not crash when there is no extension (asterisk[20])

[Holger Hans Peter Freyther]

Holger Hans Peter Freyther has uploaded this change for review. ( https://gerrit.asterisk.org/c/asterisk/+/19717 )


Change subject: res_http_media_cache: Do not crash when there is no extension
......................................................................

res_http_media_cache: Do not crash when there is no extension

Do not crash when a URL has no path component. In this case the
ast_uri_path function will return NULL. Make the code cope with
str being NULL.

The below would crash
> media cache create http://google.com /tmp/foo.wav

Thread 1 "asterisk" received signal SIGSEGV, Segmentation fault.
0x0000ffff836616cc in strrchr () from /lib/aarch64-linux-gnu/libc.so.6
(gdb) bt
 #0  0x0000ffff836616cc in strrchr () from /lib/aarch64-linux-gnu/libc.so.6
 #1  0x0000ffff43d43a78 in file_extension_from_string (str=<optimized out>, buffer=buffer at entry=0xffffca9973c0 "",
    capacity=capacity at entry=64) at res_http_media_cache.c:288
 #2  0x0000ffff43d43bac in file_extension_from_url_path (bucket_file=bucket_file at entry=0x3bf96568,
    buffer=buffer at entry=0xffffca9973c0 "", capacity=capacity at entry=64) at res_http_media_cache.c:378
 #3  0x0000ffff43d43c74 in bucket_file_set_extension (bucket_file=bucket_file at entry=0x3bf96568) at res_http_media_cache.c:392
 #4  0x0000ffff43d43d10 in bucket_file_run_curl (bucket_file=0x3bf96568) at res_http_media_cache.c:555
 #5  0x0000ffff43d43f74 in bucket_http_wizard_create (sorcery=<optimized out>, data=<optimized out>, object=<optimized out>)
    at res_http_media_cache.c:613
 #6  0x0000000000487638 in bucket_file_wizard_create (sorcery=<optimized out>, data=<optimized out>, object=<optimized out>)
    at bucket.c:191
 #7  0x0000000000554408 in sorcery_wizard_create (object_wizard=object_wizard at entry=0x3b9f0718,
    details=details at entry=0xffffca9974a8) at sorcery.c:2027
 #8  0x0000000000559698 in ast_sorcery_create (sorcery=<optimized out>, object=object at entry=0x3bf96568) at sorcery.c:2077
 #9  0x00000000004893a4 in ast_bucket_file_create (file=file at entry=0x3bf96568) at bucket.c:727
 #10 0x00000000004f877c in ast_media_cache_create_or_update (uri=0x3bfa1103 "https://google.com",
    file_path=0x3bfa1116 "/tmp/foo.wav", metadata=metadata at entry=0x0) at media_cache.c:335
 #11 0x00000000004f88ec in media_cache_handle_create_item (e=<optimized out>, cmd=<optimized out>, a=0xffffca9976b8)
    at media_cache.c:640

Change-Id: I6a9433688cb5d3d4be8758b7642d923bdde6c273
---
M res/res_http_media_cache.c
1 file changed, 46 insertions(+), 5 deletions(-)



  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/17/19717/1

diff --git a/res/res_http_media_cache.c b/res/res_http_media_cache.c
index cd5fe42..d369aed 100644
--- a/res/res_http_media_cache.c
+++ b/res/res_http_media_cache.c
@@ -160,11 +160,13 @@
 {
 	const char *ext;
 
-	ext = strrchr(str, '.');
-	if (ext && ast_get_format_for_file_ext(ext + 1)) {
-		ast_debug(3, "Found extension '%s' at end of string\n", ext);
-		ast_copy_string(buffer, ext, capacity);
-		return buffer;
+	if (str) {
+		ext = strrchr(str, '.');
+		if (ext && ast_get_format_for_file_ext(ext + 1)) {
+			ast_debug(3, "Found extension '%s' at end of string\n", ext);
+			ast_copy_string(buffer, ext, capacity);
+			return buffer;
+		}
 	}
 
 	return NULL;

-- 
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Gerrit-Project: asterisk
Gerrit-Branch: 20
Gerrit-Change-Id: I6a9433688cb5d3d4be8758b7642d923bdde6c273
Gerrit-Change-Number: 19717
Gerrit-PatchSet: 1
Gerrit-Owner: Holger Hans Peter Freyther <automatic at freyther.de>
Gerrit-MessageType: newchange
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