** Description changed:
[Impact]
When running in a multithreaded environment each pthread that opens the
/var/lib/sss/pipes/nss socket retains the file descriptor in a thread
specific structure. This file descriptor should be closed when the
thread is destroyed but due to a bug it is left open thus generating the
leak.
[Test Plan]
This code generates many threads that open the mentioned socket.
+ Install the needed packages:
+
+ $ sudo apt install sssd build-essential
+ $ cat > test_code.c < EOF
#include <pwd.h>
#include <unistd.h>
#include <pthread.h>
static void *client(void *arg)
{
int i = *((int *)arg);
struct passwd pwd;
char buf[10000];
struct passwd *r;
getpwuid_r(i, &pwd, buf, 10000, &r);
return NULL;
}
int main(void)
{
pthread_t thread;
int arg;
void *t_ret;
for (int i = 0; i < 1000; ++i) {
arg = 100000+i;
pthread_create(&thread, NULL, client, &arg);
pthread_join(thread, &t_ret);
}
while (1) {
sleep(1);
}
return 0;
}
+ EOF
+ $ gcc -o test_code test_code.c -lpthread
+ $ ./test_code
The file descriptor leak problem can be tested by compiling this code as
a test_code binary for example and running
lsof -p `pidof test_code` | wc -l
The count can reach more than a thousand when should not be bigger than
around 20 normally.
[Where problems could occur]
The patched code correctly accesses the thread specific structure to get
the file descriptor and close the socket. Previously it just considered
the structure was null and did nothing. The only new problems that could
occur are related to the closing of the socket but that would be not
worse than the previous situation.
[Other Info]
This bug only affects Noble. This is the original github issue that was
patched:
https://github.com/SSSD/sssd/issues/7189
** Description changed:
[Impact]
When running in a multithreaded environment each pthread that opens the
/var/lib/sss/pipes/nss socket retains the file descriptor in a thread
specific structure. This file descriptor should be closed when the
thread is destroyed but due to a bug it is left open thus generating the
leak.
[Test Plan]
This code generates many threads that open the mentioned socket.
-
- Install the needed packages:
$ sudo apt install sssd build-essential
$ cat > test_code.c < EOF
#include <pwd.h>
#include <unistd.h>
#include <pthread.h>
static void *client(void *arg)
{
int i = *((int *)arg);
struct passwd pwd;
char buf[10000];
struct passwd *r;
getpwuid_r(i, &pwd, buf, 10000, &r);
return NULL;
}
int main(void)
{
pthread_t thread;
int arg;
void *t_ret;
for (int i = 0; i < 1000; ++i) {
arg = 100000+i;
pthread_create(&thread, NULL, client, &arg);
pthread_join(thread, &t_ret);
}
while (1) {
sleep(1);
}
return 0;
}
EOF
$ gcc -o test_code test_code.c -lpthread
$ ./test_code
The file descriptor leak problem can be tested by compiling this code as
a test_code binary for example and running
- lsof -p `pidof test_code` | wc -l
+ $ lsof -p `pidof test_code` | wc -l
The count can reach more than a thousand when should not be bigger than
around 20 normally.
[Where problems could occur]
The patched code correctly accesses the thread specific structure to get
the file descriptor and close the socket. Previously it just considered
the structure was null and did nothing. The only new problems that could
occur are related to the closing of the socket but that would be not
worse than the previous situation.
[Other Info]
This bug only affects Noble. This is the original github issue that was
patched:
https://github.com/SSSD/sssd/issues/7189
+
+ Fixed in commit:
+ commit b439847bc88ad7b89f0596af822c0ffbf2a579df
+ From: Sumit Bose <sb...@redhat.com>
+ Date: Tue, 23 Jan 2024 09:28:26 +0100
+ Subject: sss-client: handle key value in destructor
+ Link: https://github.com/SSSD/sssd/commit/b439847
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https://bugs.launchpad.net/bugs/2085389
Title:
File descriptor leak on /var/lib/sss/pipes/nss socket
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