linux-kernel - [PATCH] modpost: Stop grab_file() from leaking filedescriptors if fstat() fails

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Date:	Sun, 22 Apr 2012 20:40:49 +0200 (CEST)
From:	Jesper Juhl <jj@...osbits.net>
To:	linux-kernel@...r.kernel.org
cc:	Rusty Russell <rusty@...tcorp.com.au>,
	Alessio Igor Bogani <abogani@...nel.org>,
	Tony Lindgren <tony@...mide.com>,
	Ben Hutchings <ben@...adent.org.uk>,
	Russell King <rmk+kernel@....linux.org.uk>
Subject: [PATCH] modpost: Stop grab_file() from leaking filedescriptors if
 fstat() fails

In case the open() call succeeds but the subsequent fstat() call
fails, then we'll return without close()'ing the filedescriptor.

Signed-off-by: Jesper Juhl <jj@...osbits.net>
---
 scripts/mod/modpost.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index c4e7d15..ea0eaca 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -337,17 +337,20 @@ static void sym_update_crc(const char *name, struct module *mod,
 void *grab_file(const char *filename, unsigned long *size)
 {
 	struct stat st;
-	void *map;
+	void *map = MAP_FAILED;
 	int fd;
 
 	fd = open(filename, O_RDONLY);
-	if (fd < 0 || fstat(fd, &st) != 0)
+	if (fd < 0)
 		return NULL;
+	if (fstat(fd, &st))
+		goto failed;
 
 	*size = st.st_size;
 	map = mmap(NULL, *size, PROT_READ|PROT_WRITE, MAP_PRIVATE, fd, 0);
-	close(fd);
 
+failed:
+	close(fd);
 	if (map == MAP_FAILED)
 		return NULL;
 	return map;
-- 
1.7.10


-- 
Jesper Juhl <jj@...osbits.net>       http://www.chaosbits.net/
Don't top-post http://www.catb.org/jargon/html/T/top-post.html
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