Check underlying hopen() worked for preload: URLs

daviesrob · whitwham · commit b14639f9eb6c · 2024-08-16T16:09:41.000+01:00
Otherwise, we might try to hread() a NULL pointer.

Credit to OSS_Fuzz
Fixes oss-fuzz id 71069
diff --git a/hfile.c b/hfile.c
@@ -703,7 +703,7 @@ static int is_preload_url_remote(const char *url){
 
 static hFILE *hopen_preload(const char *url, const char *mode){
     hFILE* fp = hopen(url + 8, mode);
-    return hpreload(fp);
+    return fp ? hpreload(fp) : NULL;
 }
 
 hFILE *hdopen(int fd, const char *mode)

Original file line number	Diff line number	Diff line change
`@@ -703,7 +703,7 @@ static int is_preload_url_remote(const char *url){`
`703`	`703`
`704`	`704`	`static hFILE hopen_preload(const char url, const char *mode){`
`705`	`705`	`hFILE* fp = hopen(url + 8, mode);`
`706`		`- return hpreload(fp);`
	`706`	`+ return fp ? hpreload(fp) : NULL;`
`707`	`707`	`}`
`708`	`708`
`709`	`709`	`hFILE hdopen(int fd, const char mode)`