[PATCH] x86: mkpiggy.c: fix resource leakage

[PATCH] x86: mkpiggy.c: fix resource leakage

[Geyslan G. Bem]

Even though the resource is released when the application is closed or
when returned from main function, modified to make it in accordance.
Now FILE pointer is always verified.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
---
 arch/x86/boot/compressed/mkpiggy.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index 958a641..b669ab6 100644
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -36,11 +36,12 @@ int main(int argc, char *argv[])
 	uint32_t olen;
 	long ilen;
 	unsigned long offs;
-	FILE *f;
+	FILE *f = NULL;
+	int retval = 1;
 
 	if (argc < 2) {
 		fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
-		return 1;
+		goto bail;
 	}
 
 	/* Get the information for the compressed kernel image first */
@@ -48,7 +49,7 @@ int main(int argc, char *argv[])
 	f = fopen(argv[1], "r");
 	if (!f) {
 		perror(argv[1]);
-		return 1;
+		goto bail;
 	}
 
 
@@ -58,12 +59,11 @@ int main(int argc, char *argv[])
 
 	if (fread(&olen, sizeof(olen), 1, f) != 1) {
 		perror(argv[1]);
-		return 1;
+		goto bail;
 	}
 
 	ilen = ftell(f);
 	olen = get_unaligned_le32(&olen);
-	fclose(f);
 
 	/*
 	 * Now we have the input (compressed) and output (uncompressed)
@@ -91,5 +91,9 @@ int main(int argc, char *argv[])
 	printf(".incbin \"%s\"\n", argv[1]);
 	printf("input_data_end:\n");
 
-	return 0;
+	retval = 0;
+bail:
+	if (f)
+		fclose(f);
+	return retval;
 }
-- 
1.8.4

Re: [PATCH] x86: mkpiggy.c: fix resource leakage

[H. Peter Anvin]

On 10/07/2013 03:16 PM, Geyslan G. Bem wrote:
> Even though the resource is released when the application is closed or
> when returned from main function, modified to make it in accordance.
> Now FILE pointer is always verified.
> 
> Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>

Perhaps you could explain what problem is solved by this patch?

Note that for correctness we really should check the return value from
fclose().

	-hpa

Re: [PATCH] x86: mkpiggy.c: fix resource leakage

[H. Peter Anvin]

On 10/07/2013 03:16 PM, Geyslan G. Bem wrote:
> Even though the resource is released when the application is closed or
> when returned from main function, modified to make it in accordance.
> Now FILE pointer is always verified.

By the way, the subject is misleading - there is no resource leakage
since the program is terminated anyway.

	-hpa

Re: [PATCH] x86: mkpiggy.c: fix resource leakage

[Geyslan Gregório Bem]

Peter,

Yes, Really doesn't have leakage, I explained it. The changes are just
to cleanup the code following a secure pattern.

Geyslan Gregório Bem
hackingbits.com


2013/10/7 H. Peter Anvin <hpa@zytor.com>:
> On 10/07/2013 03:16 PM, Geyslan G. Bem wrote:
>> Even though the resource is released when the application is closed or
>> when returned from main function, modified to make it in accordance.
>> Now FILE pointer is always verified.
>
> By the way, the subject is misleading - there is no resource leakage
> since the program is terminated anyway.
>
>         -hpa
>
>

[tip:x86/cleanups] x86: mkpiggy.c: Explicitly close the output file

[tip-bot for Geyslan G. Bem]

Commit-ID:  49449c30c4d1514486364d1e0dbea6938914b86f
Gitweb:     http://git.kernel.org/tip/49449c30c4d1514486364d1e0dbea6938914b86f
Author:     Geyslan G. Bem <geyslan@gmail.com>
AuthorDate: Mon, 7 Oct 2013 19:16:59 -0300
Committer:  H. Peter Anvin <hpa@linux.intel.com>
CommitDate: Tue, 8 Oct 2013 11:36:09 -0700

x86: mkpiggy.c: Explicitly close the output file

Even though the resource is released when the application is closed or
when returned from main function, modify the code to make it obvious,
and to keep static analysis tools from complaining.

Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Link: http://lkml.kernel.org/r/1381184219-10985-1-git-send-email-geyslan@gmail.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/boot/compressed/mkpiggy.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index 958a641..b669ab6 100644
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -36,11 +36,12 @@ int main(int argc, char *argv[])
 	uint32_t olen;
 	long ilen;
 	unsigned long offs;
-	FILE *f;
+	FILE *f = NULL;
+	int retval = 1;
 
 	if (argc < 2) {
 		fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
-		return 1;
+		goto bail;
 	}
 
 	/* Get the information for the compressed kernel image first */
@@ -48,7 +49,7 @@ int main(int argc, char *argv[])
 	f = fopen(argv[1], "r");
 	if (!f) {
 		perror(argv[1]);
-		return 1;
+		goto bail;
 	}
 
 
@@ -58,12 +59,11 @@ int main(int argc, char *argv[])
 
 	if (fread(&olen, sizeof(olen), 1, f) != 1) {
 		perror(argv[1]);
-		return 1;
+		goto bail;
 	}
 
 	ilen = ftell(f);
 	olen = get_unaligned_le32(&olen);
-	fclose(f);
 
 	/*
 	 * Now we have the input (compressed) and output (uncompressed)
@@ -91,5 +91,9 @@ int main(int argc, char *argv[])
 	printf(".incbin \"%s\"\n", argv[1]);
 	printf("input_data_end:\n");
 
-	return 0;
+	retval = 0;
+bail:
+	if (f)
+		fclose(f);
+	return retval;
 }