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coredump: retrieve comm information from /proc

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Kernel mangles comm information in an irreversible way when comm
constains repeated spaces. Retrieve comm information from /proc, and
only fallback to the information provided on the commandline when
retrieving information from /proc fails.

Add exe information to the list of saved xattr.

https://bugs.freedesktop.org/show_bug.cgi?id=62043
This commit is contained in:
Zbigniew Jędrzejewski-Szmek
2014-06-23 23:14:54 -04:00
parent 75a59316ea
commit 1eef15b181
1 changed files with 83 additions and 50 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/journal/coredump.c
+83 -50
View File
@@ -31,6 +31,7 @@
#include "log.h" #include "log.h"
#include "util.h" #include "util.h"
#include "strv.h"
#include "macro.h" #include "macro.h"
#include "mkdir.h" #include "mkdir.h"
#include "special.h" #include "special.h"
@@ -62,13 +63,14 @@
assert_cc(JOURNAL_SIZE_MAX <= ENTRY_SIZE_MAX); assert_cc(JOURNAL_SIZE_MAX <= ENTRY_SIZE_MAX);
enum { enum {
ARG_PID = 1, INFO_PID,
ARG_UID, INFO_UID,
ARG_GID, INFO_GID,
ARG_SIGNAL, INFO_SIGNAL,
ARG_TIMESTAMP, INFO_TIMESTAMP,
ARG_COMM, INFO_COMM,
_ARG_MAX INFO_EXE,
_INFO_LEN
}; };
typedef enum CoredumpStorage { typedef enum CoredumpStorage {
@@ -159,28 +161,32 @@ static int fix_acl(int fd, uid_t uid) {
return 0; return 0;
} }
static int fix_xattr(int fd, char *argv[]) { static int fix_xattr(int fd, const char *info[_INFO_LEN]) {
static const char * const xattrs[_ARG_MAX] = { static const char * const xattrs[_INFO_LEN] = {
[ARG_PID] = "user.coredump.pid", [INFO_PID] = "user.coredump.pid",
[ARG_UID] = "user.coredump.uid", [INFO_UID] = "user.coredump.uid",
[ARG_GID] = "user.coredump.gid", [INFO_GID] = "user.coredump.gid",
[ARG_SIGNAL] = "user.coredump.signal", [INFO_SIGNAL] = "user.coredump.signal",
[ARG_TIMESTAMP] = "user.coredump.timestamp", [INFO_TIMESTAMP] = "user.coredump.timestamp",
[ARG_COMM] = "user.coredump.comm", [INFO_COMM] = "user.coredump.comm",
[INFO_EXE] = "user.coredump.exe",
}; };
int r = 0; int r = 0;
unsigned i; unsigned i;
/* Attach some metadate to coredumps via extended /* Attach some metadata to coredumps via extended
* attributes. Just because we can. */ * attributes. Just because we can. */
for (i = 0; i < _ARG_MAX; i++) { for (i = 0; i < _INFO_LEN; i++) {
if (isempty(argv[i])) int k;
if (isempty(info[i]) || !xattrs[i])
continue; continue;
if (fsetxattr(fd, xattrs[i], argv[i], strlen(argv[i]), XATTR_CREATE) < 0) k = fsetxattr(fd, xattrs[i], info[i], strlen(info[i]), XATTR_CREATE);
if (k < 0 && r == 0)
r = -errno; r = -errno;
} }
@@ -189,27 +195,32 @@ static int fix_xattr(int fd, char *argv[]) {
#define filename_escape(s) xescape((s), "./ ") #define filename_escape(s) xescape((s), "./ ")
static int save_external_coredump(char **argv, uid_t uid, char **ret_filename, int *ret_fd, off_t *ret_size) { static int save_external_coredump(const char *info[_INFO_LEN],
uid_t uid,
char **ret_filename,
int *ret_fd,
off_t *ret_size) {
_cleanup_free_ char *p = NULL, *t = NULL, *c = NULL, *fn = NULL, *tmp = NULL; _cleanup_free_ char *p = NULL, *t = NULL, *c = NULL, *fn = NULL, *tmp = NULL;
_cleanup_close_ int fd = -1; _cleanup_close_ int fd = -1;
sd_id128_t boot; sd_id128_t boot;
struct stat st; struct stat st;
int r; int r;
assert(argv); assert(info);
assert(ret_filename); assert(ret_filename);
assert(ret_fd); assert(ret_fd);
assert(ret_size); assert(ret_size);
c = filename_escape(argv[ARG_COMM]); c = filename_escape(info[INFO_COMM]);
if (!c) if (!c)
return log_oom(); return log_oom();
p = filename_escape(argv[ARG_PID]); p = filename_escape(info[INFO_PID]);
if (!p) if (!p)
return log_oom(); return log_oom();
t = filename_escape(argv[ARG_TIMESTAMP]); t = filename_escape(info[INFO_TIMESTAMP]);
if (!t) if (!t)
return log_oom(); return log_oom();
@@ -242,10 +253,12 @@ static int save_external_coredump(char **argv, uid_t uid, char **ret_filename, i
r = copy_bytes(STDIN_FILENO, fd, arg_process_size_max); r = copy_bytes(STDIN_FILENO, fd, arg_process_size_max);
if (r == -E2BIG) { if (r == -E2BIG) {
log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.", argv[ARG_PID], argv[ARG_COMM]); log_error("Coredump of %s (%s) is larger than configured processing limit, refusing.",
info[INFO_PID], info[INFO_COMM]);
goto fail; goto fail;
} else if (IN_SET(r, -EDQUOT, -ENOSPC)) { } else if (IN_SET(r, -EDQUOT, -ENOSPC)) {
log_error("Not enough disk space for coredump of %s (%s), refusing.", argv[ARG_PID], argv[ARG_COMM]); log_error("Not enough disk space for coredump of %s (%s), refusing.",
info[INFO_PID], info[INFO_COMM]);
goto fail; goto fail;
} else if (r < 0) { } else if (r < 0) {
log_error("Failed to dump coredump to file: %s", strerror(-r)); log_error("Failed to dump coredump to file: %s", strerror(-r));
@@ -255,22 +268,22 @@ static int save_external_coredump(char **argv, uid_t uid, char **ret_filename, i
/* Ignore errors on these */ /* Ignore errors on these */
fchmod(fd, 0640); fchmod(fd, 0640);
fix_acl(fd, uid); fix_acl(fd, uid);
fix_xattr(fd, argv); fix_xattr(fd, info);
if (fsync(fd) < 0) { if (fsync(fd) < 0) {
log_error("Failed to sync coredump: %m"); log_error("Failed to sync coredump %s: %m", tmp);
r = -errno; r = -errno;
goto fail; goto fail;
} }
if (fstat(fd, &st) < 0) { if (fstat(fd, &st) < 0) {
log_error("Failed to fstat coredump: %m"); log_error("Failed to fstat coredump %s: %m", tmp);
r = -errno; r = -errno;
goto fail; goto fail;
} }
if (rename(tmp, fn) < 0) { if (rename(tmp, fn) < 0) {
log_error("Failed to rename coredump: %m"); log_error("Failed to rename coredump %s -> %s: %m", tmp, fn);
r = -errno; r = -errno;
goto fail; goto fail;
} }
@@ -351,7 +364,8 @@ int main(int argc, char* argv[]) {
*core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL, *core_timestamp = NULL, *core_comm = NULL, *core_exe = NULL, *core_unit = NULL,
*core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *coredump_data = NULL, *core_session = NULL, *core_message = NULL, *core_cmdline = NULL, *coredump_data = NULL,
*coredump_filename = NULL, *core_slice = NULL, *core_cgroup = NULL, *core_owner_uid = NULL, *coredump_filename = NULL, *core_slice = NULL, *core_cgroup = NULL, *core_owner_uid = NULL,
*exe = NULL; *exe = NULL, *comm = NULL;
const char *info[_INFO_LEN];
_cleanup_close_ int coredump_fd = -1; _cleanup_close_ int coredump_fd = -1;
@@ -372,8 +386,9 @@ int main(int argc, char* argv[]) {
log_set_target(LOG_TARGET_KMSG); log_set_target(LOG_TARGET_KMSG);
log_open(); log_open();
if (argc != _ARG_MAX) { if (argc < INFO_COMM + 1) {
log_error("Invalid number of arguments passed from kernel."); log_error("Not enough arguments passed from kernel (%d, expected %d).",
argc - 1, INFO_COMM + 1 - 1);
r = -EINVAL; r = -EINVAL;
goto finish; goto finish;
} }
@@ -389,24 +404,40 @@ int main(int argc, char* argv[]) {
goto finish; goto finish;
} }
r = parse_uid(argv[ARG_UID], &uid); r = parse_uid(argv[INFO_UID + 1], &uid);
if (r < 0) { if (r < 0) {
log_error("Failed to parse UID."); log_error("Failed to parse UID.");
goto finish; goto finish;
} }
r = parse_pid(argv[ARG_PID], &pid); r = parse_pid(argv[INFO_PID + 1], &pid);
if (r < 0) { if (r < 0) {
log_error("Failed to parse PID."); log_error("Failed to parse PID.");
goto finish; goto finish;
} }
r = parse_gid(argv[ARG_GID], &gid); r = parse_gid(argv[INFO_GID + 1], &gid);
if (r < 0) { if (r < 0) {
log_error("Failed to parse GID."); log_error("Failed to parse GID.");
goto finish; goto finish;
} }
if (get_process_comm(pid, &comm) < 0) {
log_warning("Failed to get COMM, falling back to the commandline.");
comm = strv_join(argv + INFO_COMM + 1, " ");
}
if (get_process_exe(pid, &exe) < 0)
log_warning("Failed to get EXE.");
info[INFO_PID] = argv[INFO_PID + 1];
info[INFO_UID] = argv[INFO_UID + 1];
info[INFO_GID] = argv[INFO_GID + 1];
info[INFO_SIGNAL] = argv[INFO_SIGNAL + 1];
info[INFO_TIMESTAMP] = argv[INFO_TIMESTAMP + 1];
info[INFO_COMM] = comm;
info[INFO_EXE] = exe;
if (cg_pid_get_unit(pid, &t) >= 0) { if (cg_pid_get_unit(pid, &t) >= 0) {
if (streq(t, SPECIAL_JOURNALD_SERVICE)) { if (streq(t, SPECIAL_JOURNALD_SERVICE)) {
@@ -418,7 +449,7 @@ int main(int argc, char* argv[]) {
if (arg_storage != COREDUMP_STORAGE_NONE) if (arg_storage != COREDUMP_STORAGE_NONE)
arg_storage = COREDUMP_STORAGE_EXTERNAL; arg_storage = COREDUMP_STORAGE_EXTERNAL;
r = save_external_coredump(argv, uid, &coredump_filename, &coredump_fd, &coredump_size); r = save_external_coredump(info, uid, &coredump_filename, &coredump_fd, &coredump_size);
if (r < 0) if (r < 0)
goto finish; goto finish;
@@ -442,26 +473,22 @@ int main(int argc, char* argv[]) {
log_set_target(LOG_TARGET_JOURNAL_OR_KMSG); log_set_target(LOG_TARGET_JOURNAL_OR_KMSG);
log_open(); log_open();
core_pid = strappend("COREDUMP_PID=", argv[ARG_PID]); core_pid = strappend("COREDUMP_PID=", info[INFO_PID]);
if (core_pid) if (core_pid)
IOVEC_SET_STRING(iovec[j++], core_pid); IOVEC_SET_STRING(iovec[j++], core_pid);
core_uid = strappend("COREDUMP_UID=", argv[ARG_UID]); core_uid = strappend("COREDUMP_UID=", info[INFO_UID]);
if (core_uid) if (core_uid)
IOVEC_SET_STRING(iovec[j++], core_uid); IOVEC_SET_STRING(iovec[j++], core_uid);
core_gid = strappend("COREDUMP_GID=", argv[ARG_GID]); core_gid = strappend("COREDUMP_GID=", info[INFO_GID]);
if (core_gid) if (core_gid)
IOVEC_SET_STRING(iovec[j++], core_gid); IOVEC_SET_STRING(iovec[j++], core_gid);
core_signal = strappend("COREDUMP_SIGNAL=", argv[ARG_SIGNAL]); core_signal = strappend("COREDUMP_SIGNAL=", info[INFO_SIGNAL]);
if (core_signal) if (core_signal)
IOVEC_SET_STRING(iovec[j++], core_signal); IOVEC_SET_STRING(iovec[j++], core_signal);
core_comm = strappend("COREDUMP_COMM=", argv[ARG_COMM]);
if (core_comm)
IOVEC_SET_STRING(iovec[j++], core_comm);
if (sd_pid_get_session(pid, &t) >= 0) { if (sd_pid_get_session(pid, &t) >= 0) {
core_session = strappend("COREDUMP_SESSION=", t); core_session = strappend("COREDUMP_SESSION=", t);
free(t); free(t);
@@ -485,7 +512,13 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], core_slice); IOVEC_SET_STRING(iovec[j++], core_slice);
} }
if (get_process_exe(pid, &exe) >= 0) { if (comm) {
core_comm = strappend("COREDUMP_COMM=", comm);
if (core_comm)
IOVEC_SET_STRING(iovec[j++], core_comm);
}
if (exe) {
core_exe = strappend("COREDUMP_EXE=", exe); core_exe = strappend("COREDUMP_EXE=", exe);
if (core_exe) if (core_exe)
IOVEC_SET_STRING(iovec[j++], core_exe); IOVEC_SET_STRING(iovec[j++], core_exe);
@@ -507,7 +540,7 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], core_cgroup); IOVEC_SET_STRING(iovec[j++], core_cgroup);
} }
core_timestamp = strjoin("COREDUMP_TIMESTAMP=", argv[ARG_TIMESTAMP], "000000", NULL); core_timestamp = strjoin("COREDUMP_TIMESTAMP=", info[INFO_TIMESTAMP], "000000", NULL);
if (core_timestamp) if (core_timestamp)
IOVEC_SET_STRING(iovec[j++], core_timestamp); IOVEC_SET_STRING(iovec[j++], core_timestamp);
@@ -515,7 +548,7 @@ int main(int argc, char* argv[]) {
IOVEC_SET_STRING(iovec[j++], "PRIORITY=2"); IOVEC_SET_STRING(iovec[j++], "PRIORITY=2");
/* Always stream the coredump to disk, if that's possible */ /* Always stream the coredump to disk, if that's possible */
r = save_external_coredump(argv, uid, &coredump_filename, &coredump_fd, &coredump_size); r = save_external_coredump(info, uid, &coredump_filename, &coredump_fd, &coredump_size);
if (r < 0) if (r < 0)
goto finish; goto finish;
@@ -546,14 +579,14 @@ int main(int argc, char* argv[]) {
r = coredump_make_stack_trace(coredump_fd, exe, &stacktrace); r = coredump_make_stack_trace(coredump_fd, exe, &stacktrace);
if (r >= 0) if (r >= 0)
core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") of user ", argv[ARG_UID], " dumped core.\n\n", stacktrace, NULL); core_message = strjoin("MESSAGE=Process ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.\n\n", stacktrace, NULL);
else else
log_warning("Failed to generate stack trace: %s", strerror(-r)); log_warning("Failed to generate stack trace: %s", strerror(-r));
} }
if (!core_message) if (!core_message)
#endif #endif
core_message = strjoin("MESSAGE=Process ", argv[ARG_PID], " (", argv[ARG_COMM], ") of user ", argv[ARG_UID], " dumped core.", NULL); core_message = strjoin("MESSAGE=Process ", info[INFO_PID], " (", comm, ") of user ", info[INFO_UID], " dumped core.", NULL);
if (core_message) if (core_message)
IOVEC_SET_STRING(iovec[j++], core_message); IOVEC_SET_STRING(iovec[j++], core_message);