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Sanitise the coredump file names sent to devd.

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While there, add a sysctl to turn this feature off as requested by
kib@.
This commit is contained in:
Rui Paulo 2015-02-10 04:34:39 +00:00
parent 35994c42c3
commit eb6368d4f8
1 changed files with 40 additions and 17 deletions
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57
sys/kern/kern_sig.c
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@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
#include "opt_core.h"
#include <sys/param.h>
#include <sys/ctype.h>
#include <sys/systm.h>
#include <sys/signalvar.h>
#include <sys/vnode.h>
@ -179,6 +180,10 @@ static int set_core_nodump_flag = 0;
SYSCTL_INT(_kern, OID_AUTO, nodump_coredump, CTLFLAG_RW, &set_core_nodump_flag,
0, "Enable setting the NODUMP flag on coredump files");
static int coredump_devctl = 1;
SYSCTL_INT(_kern, OID_AUTO, coredump_devctl, CTLFLAG_RW, &coredump_devctl,
0, "Generate a devctl notification when processes coredump");
/*
* Signal properties and actions.
* The array below categorizes the signals and their default actions
@ -3217,6 +3222,25 @@ corefile_open(const char *comm, uid_t uid, pid_t pid, struct thread *td,
return (0);
}
static int
coredump_sanitise_path(const char *path)
{
size_t len, i;
/*
* Only send a subset of ASCII to devd(8) because it
* might pass these strings to sh -c.
*/
len = strlen(path);
for (i = 0; i < len; i++)
if (!(isalpha(path[i]) || isdigit(path[i])) &&
path[i] != '/' && path[i] != '.' &&
path[i] != '-')
return (0);
return (1);
}
/*
* Dump a process' core. The main routine does some
* policy checking, and creates the name of the coredump;
@ -3238,9 +3262,9 @@ coredump(struct thread *td)
void *rl_cookie;
off_t limit;
int compress;
char *data = NULL;
size_t len;
char data[MAXPATHLEN * 2 + 16]; /* space for devctl notification */
char *fullpath, *freepath = NULL;
size_t len;
#ifdef COMPRESS_USER_CORES
compress = compress_user_cores;
@ -3332,30 +3356,29 @@ coredump(struct thread *td)
* Notify the userland helper that a process triggered a core dump.
* This allows the helper to run an automated debugging session.
*/
len = MAXPATHLEN * 2 + 5 /* comm= */ + 5 /* core= */ + 1;
data = malloc(len, M_TEMP, M_NOWAIT);
if (data == NULL)
if (coredump_devctl == 0)
goto out;
if (vn_fullpath_global(td, p->p_textvp, &fullpath, &freepath) != 0)
goto out;
snprintf(data, len, "comm=%s", fullpath);
if (freepath != NULL) {
free(freepath, M_TEMP);
freepath = NULL;
}
if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0)
if (!coredump_sanitise_path(fullpath))
goto out;
snprintf(data, len, "%s core=%s", data, fullpath);
snprintf(data, sizeof(data), "comm=%s ", fullpath);
free(freepath, M_TEMP);
freepath = NULL;
if (vn_fullpath_global(td, vp, &fullpath, &freepath) != 0) {
printf("could not find coredump\n");
goto out;
}
if (!coredump_sanitise_path(fullpath))
goto out;
strlcat(data, "core=", sizeof(data));
len = strlcat(data, fullpath, sizeof(data));
devctl_notify("kernel", "signal", "coredump", data);
free(name, M_TEMP);
out:
#ifdef AUDIT
audit_proc_coredump(td, name, error);
#endif
if (freepath != NULL)
free(freepath, M_TEMP);
if (data != NULL)
free(data, M_TEMP);
free(freepath, M_TEMP);
free(name, M_TEMP);
return (error);
}