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

[Friendly Automation]

Friendly Automation has submitted this change. ( 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 as in this case the
ast_uri_path function will return NULL. Make the code cope with not
having a path.

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

ASTERISK-30375 #close

Change-Id: I6a9433688cb5d3d4be8758b7642d923bdde6c273
---
M res/res_http_media_cache.c
1 file changed, 49 insertions(+), 1 deletion(-)

Approvals:
  Joshua Colp: Looks good to me, but someone else must approve
  Sean Bright: Looks good to me, but someone else must approve
  George Joseph: Looks good to me, approved
  Friendly Automation: Approved for Submit




diff --git a/res/res_http_media_cache.c b/res/res_http_media_cache.c
index cd5fe42..b4c4c65 100644
--- a/res/res_http_media_cache.c
+++ b/res/res_http_media_cache.c
@@ -240,6 +240,7 @@
 
 static char *file_extension_from_url_path(struct ast_bucket_file *bucket_file, char *buffer, size_t capacity)
 {
+	const char *path;
 	struct ast_uri *uri;
 
 	uri = ast_uri_parse(ast_sorcery_object_get_id(bucket_file));
@@ -249,8 +250,14 @@
 		return NULL;
 	}
 
+	path = ast_uri_path(uri);
+	if (!path) {
+		ao2_cleanup(uri);
+		return NULL;
+	}
+
 	/* Just parse it as a string like before, but without the extra cruft */
-	buffer = file_extension_from_string(ast_uri_path(uri), buffer, capacity);
+	buffer = file_extension_from_string(path, buffer, capacity);
 	ao2_cleanup(uri);
 	return buffer;
 }

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Gerrit-Project: asterisk
Gerrit-Branch: 20
Gerrit-Change-Id: I6a9433688cb5d3d4be8758b7642d923bdde6c273
Gerrit-Change-Number: 19717
Gerrit-PatchSet: 4
Gerrit-Owner: Holger Hans Peter Freyther <automatic at freyther.de>
Gerrit-Reviewer: Friendly Automation
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at sangoma.com>
Gerrit-Reviewer: N A <asterisk at phreaknet.org>
Gerrit-Reviewer: Sean Bright <sean at seanbright.com>
Gerrit-MessageType: merged
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