[LTP] [PATCH 1/2] open: fix cleanup condition and use snprintf

[LTP] [PATCH 1/2] open: fix cleanup condition and use snprintf

[Jinseok Kim]

The test uses sprintf() to build temporary file names, which may
overflow the fixed-size buffer. Replace it with snprintf() to avoid
potential buffer overflows.

The cleanup logic also checked '!first' to decide whether to close
file descriptors. Since file descriptor 0 is valid, this condition
can incorrectly skip cleanup and leak file descriptors.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/open/open04.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
index 3dc3486d3..ed5dd27bb 100644
--- a/testcases/kernel/syscalls/open/open04.c
+++ b/testcases/kernel/syscalls/open/open04.c
@@ -30,7 +30,7 @@ static void setup(void)
 	fds[0] = first;

 	for (i = first + 1; i < fds_limit; i++) {
-		sprintf(fname, FNAME ".%d", i);
+		snprintf(fname, sizeof(fname), FNAME ".%d", i);
 		fd = open(fname, O_RDWR | O_CREAT, 0777);
 		if (fd == -1) {
 			if (errno != EMFILE)
@@ -50,7 +50,7 @@ static void run(void)

 static void cleanup(void)
 {
-	if (!first || !fds)
+	if (first < 0 || !fds)
 		return;

 	for (i = first; i < fds_limit; i++)
--
2.43.0

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[LTP] [PATCH 2/2] open: replace getdtablesize with getrlimit

[Jinseok Kim]

The test currently uses getdtablesize() to determine the maximum
number of file descriptors for the process. This interface is
considered legacy and is not specified by POSIX.

Use getrlimit() instead, which provides a well-defined
and portable way to obtain the per-process file descriptor limit.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/open/open04.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
index ed5dd27bb..3d8ea2ae8 100644
--- a/testcases/kernel/syscalls/open/open04.c
+++ b/testcases/kernel/syscalls/open/open04.c
@@ -11,6 +11,7 @@

 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/resource.h>
 #include "tst_test.h"

 #define FNAME "open04"
@@ -23,7 +24,10 @@ static void setup(void)
 {
 	int fd;

-	fds_limit = getdtablesize();
+	struct rlimit rlim;
+
+	SAFE_GETRLIMIT(RLIMIT_NOFILE, &rlim);
+	fds_limit = rlim.rlim_cur;
 	first = SAFE_OPEN(FNAME, O_RDWR | O_CREAT, 0777);

 	fds = SAFE_MALLOC(sizeof(int) * (fds_limit - first));
--
2.43.0

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Re: [LTP] [PATCH 2/2] open: replace getdtablesize with getrlimit

[Andrea Cervesato via ltp]

Hi!

Patch is ok, but it might be good to change `sprintf()` with `snprintf()`
in the setup() as well to ensure safety.

King regards,
-- 
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com


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[LTP] [PATCH v2 1/2] open: fix cleanup condition and use snprintf

[Jinseok Kim]

Hi Cervesato.

Thanks for the review!

Changes since v1:
- Replace remaining sprintf() with snprintf() in setup()

Thanks,
Jinseok.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/open/open04.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
index 3dc3486d3..5d39c1569 100644
--- a/testcases/kernel/syscalls/open/open04.c
+++ b/testcases/kernel/syscalls/open/open04.c
@@ -30,7 +30,7 @@ static void setup(void)
 	fds[0] = first;

 	for (i = first + 1; i < fds_limit; i++) {
-		sprintf(fname, FNAME ".%d", i);
+		snprintf(fname, sizeof(fname), FNAME ".%d", i);
 		fd = open(fname, O_RDWR | O_CREAT, 0777);
 		if (fd == -1) {
 			if (errno != EMFILE)
@@ -44,13 +44,13 @@ static void setup(void)

 static void run(void)
 {
-	sprintf(fname, FNAME ".%d", fds_limit);
+	snprintf(fname, sizeof(fname), FNAME ".%d", fds_limit);
 	TST_EXP_FAIL2(open(fname, O_RDWR | O_CREAT, 0777), EMFILE);
 }

 static void cleanup(void)
 {
-	if (!first || !fds)
+	if (first < 0 || !fds)
 		return;

 	for (i = first; i < fds_limit; i++)
--
2.43.0

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Re: [LTP] [PATCH v2 1/2] open: fix cleanup condition and use snprintf

[Andrea Cervesato via ltp]

On Tue Feb 17, 2026 at 1:22 PM CET, Jinseok Kim wrote:
> Hi Cervesato.
>
> Thanks for the review!
>
> Changes since v1:
> - Replace remaining sprintf() with snprintf() in setup()
>
> Thanks,
> Jinseok.
>
> Signed-off-by: Jinseok Kim <always.starving0@gmail.com>

Are you using an automatic tool? This seems like a wrong commit message.
Please resend the whole patch-set with a proper version and right commit
message. I will reject this one.

Kind regards,
-- 
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com


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[LTP] [PATCH v2 1/2] open: fix cleanup condition and use snprintf

[Jinseok Kim]

Replace remaining sprintf() with snprintf() in setup()

Thanks for the review.

Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
---
 testcases/kernel/syscalls/open/open04.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
index 3dc3486d3..5d39c1569 100644
--- a/testcases/kernel/syscalls/open/open04.c
+++ b/testcases/kernel/syscalls/open/open04.c
@@ -30,7 +30,7 @@ static void setup(void)
 	fds[0] = first;

 	for (i = first + 1; i < fds_limit; i++) {
-		sprintf(fname, FNAME ".%d", i);
+		snprintf(fname, sizeof(fname), FNAME ".%d", i);
 		fd = open(fname, O_RDWR | O_CREAT, 0777);
 		if (fd == -1) {
 			if (errno != EMFILE)
@@ -44,13 +44,13 @@ static void setup(void)

 static void run(void)
 {
-	sprintf(fname, FNAME ".%d", fds_limit);
+	snprintf(fname, sizeof(fname), FNAME ".%d", fds_limit);
 	TST_EXP_FAIL2(open(fname, O_RDWR | O_CREAT, 0777), EMFILE);
 }

 static void cleanup(void)
 {
-	if (!first || !fds)
+	if (first < 0 || !fds)
 		return;

 	for (i = first; i < fds_limit; i++)
--
2.43.0

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Re: [LTP] [PATCH v2 1/2] open: fix cleanup condition and use snprintf

[Andrea Cervesato via ltp]

Hi!

On Wed Feb 18, 2026 at 3:47 PM CET, Jinseok Kim wrote:
> Replace remaining sprintf() with snprintf() in setup()
>
> Thanks for the review.

Again, there's something wrong with your automated system. Is it LLM? :-)
The message is misleading, also because not only snprintf() touched, but
also cleanup() logic.

This has to be fixed, otherwise patch can't be accepted.

>
> Signed-off-by: Jinseok Kim <always.starving0@gmail.com>
> ---
>  testcases/kernel/syscalls/open/open04.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/open/open04.c b/testcases/kernel/syscalls/open/open04.c
> index 3dc3486d3..5d39c1569 100644
> --- a/testcases/kernel/syscalls/open/open04.c
> +++ b/testcases/kernel/syscalls/open/open04.c
> @@ -30,7 +30,7 @@ static void setup(void)
>  	fds[0] = first;
>
>  	for (i = first + 1; i < fds_limit; i++) {
> -		sprintf(fname, FNAME ".%d", i);
> +		snprintf(fname, sizeof(fname), FNAME ".%d", i);
>  		fd = open(fname, O_RDWR | O_CREAT, 0777);
>  		if (fd == -1) {
>  			if (errno != EMFILE)
> @@ -44,13 +44,13 @@ static void setup(void)
>
>  static void run(void)
>  {
> -	sprintf(fname, FNAME ".%d", fds_limit);
> +	snprintf(fname, sizeof(fname), FNAME ".%d", fds_limit);
>  	TST_EXP_FAIL2(open(fname, O_RDWR | O_CREAT, 0777), EMFILE);
>  }
>
>  static void cleanup(void)
>  {
> -	if (!first || !fds)
> +	if (first < 0 || !fds)

And this cleanup has an issue. See below..

>  		return;
>
>  	for (i = first; i < fds_limit; i++)
> --
> 2.43.0

This test has to work also for `-i 0` option. The way we can make it
works is the following:

- "first" should be initialized to -1, otherwise "first < 0" won't be
  catched
- the fds should be initialized with -1 after SAFE_MALLOC(), otherwise
  you will fail the cleanup if malloc will break the test


Kind Regards,
-- 
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com


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