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-rw-r--r--meta/recipes-kernel/lttng/lttng-tools/0007-Fix-getgrnam-is-not-MT-Safe-use-getgrnam_r.patch345
1 files changed, 345 insertions, 0 deletions
diff --git a/meta/recipes-kernel/lttng/lttng-tools/0007-Fix-getgrnam-is-not-MT-Safe-use-getgrnam_r.patch b/meta/recipes-kernel/lttng/lttng-tools/0007-Fix-getgrnam-is-not-MT-Safe-use-getgrnam_r.patch
new file mode 100644
index 0000000000..5437de26e8
--- /dev/null
+++ b/meta/recipes-kernel/lttng/lttng-tools/0007-Fix-getgrnam-is-not-MT-Safe-use-getgrnam_r.patch
@@ -0,0 +1,345 @@
+From 10e8001ad876d8cb3b5a17c7492e713bbc047975 Mon Sep 17 00:00:00 2001
+From: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
+Date: Thu, 28 Mar 2019 18:31:29 -0400
+Subject: [PATCH] Fix: getgrnam is not MT-Safe, use getgrnam_r
+
+Running the test suite under a Yocto musl build resulted in musl
+coredump due to double freeing.
+
+We get the following backtraces:
+
+0 a_crash () at ./arch/x86_64/atomic_arch.h:108
+1 unmap_chunk (self=<optimized out>) at src/malloc/malloc.c:515
+2 free (p=<optimized out>) at src/malloc/malloc.c:526
+3 0x00007f46d9dc3849 in __getgrent_a (f=f@entry=0x7f46d9d1f7e0, gr=gr@entry=0x7f46d9e24460 <gr>, line=line@entry=0x7f46d9e26058 <line>, size=size@entry=0x7f46d92db550, mem=mem@entry=0x7f46d9e26050 <mem>, nmem=nmem@entry=0x7f46d92db558, res=0x7f46d92db548) at src/passwd/getgrent_a.c:45
+4 0x00007f46d9dc2e6b in __getgr_a (name=0x487242 "tracing", gid=gid@entry=0, gr=gr@entry=0x7f46d9e24460 <gr>, buf=buf@entry=0x7f46d9e26058 <line>, size=size@entry=0x7f46d92db550, mem=mem@entry=0x7f46d9e26050 <mem>, nmem=0x7f46d92db558, res=0x7f46d92db548) at src/passwd/getgr_a.c:30
+5 0x00007f46d9dc3733 in getgrnam (name=<optimized out>) at src/passwd/getgrent.c:37
+6 0x0000000000460b29 in utils_get_group_id (name=<optimized out>) at ../../../lttng-tools-2.10.6/src/common/utils.c:1241
+7 0x000000000044ee69 in thread_manage_health (data=<optimized out>) at ../../../../lttng-tools-2.10.6/src/bin/lttng-sessiond/main.c:4115
+8 0x00007f46d9de1541 in start (p=<optimized out>) at src/thread/pthread_create.c:195
+9 0x00007f46d9dee661 in __clone () at src/thread/x86_64/clone.s:22
+
+From another run:
+
+0 a_crash () at ./arch/x86_64/atomic_arch.h:108
+1 unmap_chunk (self=<optimized out>) at src/malloc/malloc.c:515
+2 free (p=<optimized out>) at src/malloc/malloc.c:526
+3 0x00007f5abc210849 in __getgrent_a (f=f@entry=0x7f5abc2733e0, gr=gr@entry=0x7f5abc271460 <gr>, line=line@entry=0x7f5abc273058 <line>, size=size@entry=0x7f5abaef5510, mem=mem@entry=0x7f5abc273050 <mem>, nmem=nmem@entry=0x7f5abaef5518, res=0x7f5abaef5508) at src/passwd/getgrent_a.c:45
+4 0x00007f5abc20fe6b in __getgr_a (name=0x487242 "tracing", gid=gid@entry=0, gr=gr@entry=0x7f5abc271460 <gr>, buf=buf@entry=0x7f5abc273058 <line>, size=size@entry=0x7f5abaef5510, mem=mem@entry=0x7f5abc273050 <mem>, nmem=0x7f5abaef5518, res=0x7f5abaef5508) at src/passwd/getgr_a.c:30
+5 0x00007f5abc210733 in getgrnam (name=<optimized out>) at src/passwd/getgrent.c:37
+6 0x0000000000460b29 in utils_get_group_id (name=<optimized out>) at ../../../lttng-tools-2.10.6/src/common/utils.c:1241
+7 0x000000000042dee4 in notification_channel_socket_create () at ../../../../lttng-tools-2.10.6/src/bin/lttng-sessiond/notification-thread.c:238
+8 init_thread_state (state=0x7f5abaef5560, handle=0x7f5abbf9be40) at ../../../../lttng-tools-2.10.6/src/bin/lttng-sessiond/notification-thread.c:375
+9 thread_notification (data=0x7f5abbf9be40) at ../../../../lttng-tools-2.10.6/src/bin/lttng-sessiond/notification-thread.c:495
+10 0x00007f5abc22e541 in start (p=<optimized out>) at src/thread/pthread_create.c:195
+11 0x00007f5abc23b661 in __clone () at src/thread/x86_64/clone.s:22
+
+The problem was easily reproducible (~6 crash on ~300 runs). A prototype fix
+using mutex around the getgrnam yielded no crash in over 1000 runs. This
+patch yielded the same results as the prototype fix.
+
+Unfortunately we cannot rely on a mutex in liblttng-ctl since we cannot
+enforce the locking for the application using the lib.
+
+Use getgrnam_r instead.
+
+The previous implementation of utils_get_group_id returned the gid of
+the root group (0) on error/not found. lttng_check_tracing_group needs
+to know if an error/not found occured, returning the root group is not
+enough. We now return the gid via the passed parameter. The caller is
+responsible for either defaulting to the root group or propagating the
+error.
+
+We also do not want to warn when used in liblttng-ctl context. We might
+want to move the warning elsewhere in the future. For now, pass a bool
+if we need to warn or not.
+
+Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
+---
+ src/bin/lttng-consumerd/health-consumerd.c | 10 ++-
+ src/bin/lttng-relayd/health-relayd.c | 20 ++++--
+ src/bin/lttng-sessiond/main.c | 24 +++++--
+ src/bin/lttng-sessiond/notification-thread.c | 10 ++-
+ src/common/utils.c | 75 +++++++++++++++++---
+ src/common/utils.h | 4 +-
+ src/lib/lttng-ctl/lttng-ctl.c | 8 +--
+ 7 files changed, 122 insertions(+), 29 deletions(-)
+
+diff --git a/src/bin/lttng-consumerd/health-consumerd.c b/src/bin/lttng-consumerd/health-consumerd.c
+index 1e2f31e4..6045401a 100644
+--- a/src/bin/lttng-consumerd/health-consumerd.c
++++ b/src/bin/lttng-consumerd/health-consumerd.c
+@@ -184,8 +184,14 @@ void *thread_manage_health(void *data)
+ is_root = !getuid();
+ if (is_root) {
+ /* lttng health client socket path permissions */
+- ret = chown(health_unix_sock_path, 0,
+- utils_get_group_id(tracing_group_name));
++ gid_t gid;
++
++ ret = utils_get_group_id(tracing_group_name, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group. */
++ }
++
++ ret = chown(health_unix_sock_path, 0, gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", health_unix_sock_path);
+ PERROR("chown");
+diff --git a/src/bin/lttng-relayd/health-relayd.c b/src/bin/lttng-relayd/health-relayd.c
+index ba996621..962e88c4 100644
+--- a/src/bin/lttng-relayd/health-relayd.c
++++ b/src/bin/lttng-relayd/health-relayd.c
+@@ -105,8 +105,14 @@ static int create_lttng_rundir_with_perm(const char *rundir)
+ int is_root = !getuid();
+
+ if (is_root) {
+- ret = chown(rundir, 0,
+- utils_get_group_id(tracing_group_name));
++ gid_t gid;
++
++ ret = utils_get_group_id(tracing_group_name, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group.*/
++ }
++
++ ret = chown(rundir, 0, gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", rundir);
+ PERROR("chown");
+@@ -256,8 +262,14 @@ void *thread_manage_health(void *data)
+ is_root = !getuid();
+ if (is_root) {
+ /* lttng health client socket path permissions */
+- ret = chown(health_unix_sock_path, 0,
+- utils_get_group_id(tracing_group_name));
++ gid_t gid;
++
++ ret = utils_get_group_id(tracing_group_name, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group */
++ }
++
++ ret = chown(health_unix_sock_path, 0, gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", health_unix_sock_path);
+ PERROR("chown");
+diff --git a/src/bin/lttng-sessiond/main.c b/src/bin/lttng-sessiond/main.c
+index fa6fa483..49307064 100644
+--- a/src/bin/lttng-sessiond/main.c
++++ b/src/bin/lttng-sessiond/main.c
+@@ -4112,8 +4112,14 @@ static void *thread_manage_health(void *data)
+
+ if (is_root) {
+ /* lttng health client socket path permissions */
+- ret = chown(config.health_unix_sock_path.value, 0,
+- utils_get_group_id(config.tracing_group_name.value));
++ gid_t gid;
++
++ ret = utils_get_group_id(config.tracing_group_name.value, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group */
++ }
++
++ ret = chown(config.health_unix_sock_path.value, 0, &gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", config.health_unix_sock_path.value);
+ PERROR("chown");
+@@ -5238,7 +5244,10 @@ static int set_permissions(char *rundir)
+ int ret;
+ gid_t gid;
+
+- gid = utils_get_group_id(config.tracing_group_name.value);
++ ret = utils_get_group_id(config.tracing_group_name.value, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group */
++ }
+
+ /* Set lttng run dir */
+ ret = chown(rundir, 0, gid);
+@@ -5349,7 +5358,14 @@ static int set_consumer_sockets(struct consumer_data *consumer_data)
+ goto error;
+ }
+ if (is_root) {
+- ret = chown(path, 0, utils_get_group_id(config.tracing_group_name.value));
++ gid_t gid;
++
++ ret = utils_get_group_id(config.tracing_group_name.value, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group */
++ }
++
++ ret = chown(path, 0, gid);
+ if (ret < 0) {
+ ERR("Unable to set group on %s", path);
+ PERROR("chown");
+diff --git a/src/bin/lttng-sessiond/notification-thread.c b/src/bin/lttng-sessiond/notification-thread.c
+index 92ac597f..18a264d9 100644
+--- a/src/bin/lttng-sessiond/notification-thread.c
++++ b/src/bin/lttng-sessiond/notification-thread.c
+@@ -235,8 +235,14 @@ int notification_channel_socket_create(void)
+ }
+
+ if (getuid() == 0) {
+- ret = chown(sock_path, 0,
+- utils_get_group_id(config.tracing_group_name.value));
++ gid_t gid;
++
++ ret = utils_get_group_id(config.tracing_group_name.value, true, &gid);
++ if (ret) {
++ gid = 0; /* Default to root group. */
++ }
++
++ ret = chown(sock_path, 0, gid);
+ if (ret) {
+ ERR("Failed to set the notification channel socket's group");
+ ret = -1;
+diff --git a/src/common/utils.c b/src/common/utils.c
+index c0bb031e..778bc00f 100644
+--- a/src/common/utils.c
++++ b/src/common/utils.c
+@@ -1231,24 +1231,77 @@ size_t utils_get_current_time_str(const char *format, char *dst, size_t len)
+ }
+
+ /*
+- * Return the group ID matching name, else 0 if it cannot be found.
++ * Return 0 on success and set *gid to the group_ID matching the passed name.
++ * Else -1 if it cannot be found or an error occurred.
+ */
+ LTTNG_HIDDEN
+-gid_t utils_get_group_id(const char *name)
++int utils_get_group_id(const char *name, bool warn, gid_t *gid)
+ {
+- struct group *grp;
++ static volatile int warn_once;
+
+- grp = getgrnam(name);
+- if (!grp) {
+- static volatile int warn_once;
++ int ret;
++ long sys_len;
++ size_t len;
++ struct group grp;
++ struct group *result;
++ char *buffer = NULL;
+
+- if (!warn_once) {
+- WARN("No tracing group detected");
+- warn_once = 1;
++ /* Get the system limit if it exists */
++ sys_len = sysconf(_SC_GETGR_R_SIZE_MAX);
++ if (sys_len == -1) {
++ len = 1024;
++ } else {
++ len = (size_t) sys_len;
++ }
++
++ buffer = malloc(len);
++ if (!buffer) {
++ PERROR("getgrnam_r malloc");
++ ret = -1;
++ goto error;
++ }
++
++ while ((ret = getgrnam_r(name, &grp, buffer, len, &result)) == ERANGE)
++ {
++ /* Buffer is not big enough, increase its size. */
++ size_t new_len = 2 * len;
++ char *new_buffer = NULL;
++ if (new_len < len) {
++ ERR("getgrnam_r buffer size overflow");
++ ret = -1;
++ goto error;
++ }
++ len = new_len;
++ new_buffer = realloc(buffer, len);
++ if (!new_buffer) {
++ PERROR("getgrnam_r realloc");
++ ret = -1;
++ goto error;
+ }
+- return 0;
++ buffer = new_buffer;
++ }
++ if (ret != 0) {
++ PERROR("getgrnam_r");
++ ret = -1;
++ goto error;
++ }
++
++ /* Group not found. */
++ if (!result) {
++ ret = -1;
++ goto error;
++ }
++
++ *gid = result->gr_gid;
++ ret = 0;
++
++error:
++ free(buffer);
++ if (ret && warn && !warn_once) {
++ WARN("No tracing group detected");
++ warn_once = 1;
+ }
+- return grp->gr_gid;
++ return ret;
+ }
+
+ /*
+diff --git a/src/common/utils.h b/src/common/utils.h
+index 18f19ef1..9c72431d 100644
+--- a/src/common/utils.h
++++ b/src/common/utils.h
+@@ -22,6 +22,8 @@
+ #include <unistd.h>
+ #include <stdint.h>
+ #include <getopt.h>
++#include <stdbool.h>
++#include <sys/types.h>
+
+ #define KIBI_LOG2 10
+ #define MEBI_LOG2 20
+@@ -52,7 +54,7 @@ int utils_get_count_order_u64(uint64_t x);
+ char *utils_get_home_dir(void);
+ char *utils_get_user_home_dir(uid_t uid);
+ size_t utils_get_current_time_str(const char *format, char *dst, size_t len);
+-gid_t utils_get_group_id(const char *name);
++int utils_get_group_id(const char *name, bool warn, gid_t *gid);
+ char *utils_generate_optstring(const struct option *long_options,
+ size_t opt_count);
+ int utils_create_lock_file(const char *filepath);
+diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
+index 2d84aad9..561b0bcf 100644
+--- a/src/lib/lttng-ctl/lttng-ctl.c
++++ b/src/lib/lttng-ctl/lttng-ctl.c
+@@ -208,15 +208,13 @@ end:
+ LTTNG_HIDDEN
+ int lttng_check_tracing_group(void)
+ {
+- struct group *grp_tracing; /* no free(). See getgrnam(3) */
+- gid_t *grp_list;
++ gid_t *grp_list, tracing_gid;
+ int grp_list_size, grp_id, i;
+ int ret = -1;
+ const char *grp_name = tracing_group;
+
+ /* Get GID of group 'tracing' */
+- grp_tracing = getgrnam(grp_name);
+- if (!grp_tracing) {
++ if (utils_get_group_id(grp_name, false, &tracing_gid)) {
+ /* If grp_tracing is NULL, the group does not exist. */
+ goto end;
+ }
+@@ -241,7 +239,7 @@ int lttng_check_tracing_group(void)
+ }
+
+ for (i = 0; i < grp_list_size; i++) {
+- if (grp_list[i] == grp_tracing->gr_gid) {
++ if (grp_list[i] == tracing_gid) {
+ ret = 1;
+ break;
+ }
+--
+2.17.1
+
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-06-02 19:46:57 +0000