Bug 25298
| Summary: | dmesg -a | ||
|---|---|---|---|
| Product: | Base System | Reporter: | mitsuru <mitsuru> |
| Component: | bin | Assignee: | GNATS administrator <gnats-admin> |
| Status: | Closed FIXED | ||
| Severity: | Affects Only Me | ||
| Priority: | Normal | ||
| Version: | 1.0-RELEASE | ||
| Hardware: | Any | ||
| OS: | Any | ||
State Changed From-To: open->closed duplicate |
Originator: Mitsuru Yoshida Organization: RIKEN Confidential: no <FreeBSD PRs are public data> Synopsis: using dmesg -a should be restricted Severity: serious Priority: medium Category: bin Release: FreeBSD 4.2-STABLE i386 Class: change-request Environment: FreeBSD 4.2-STABLE i386 Description: Using dmesg -a, all data in the message buffer can be read by any user, and it may cause security problem. Especially all messages written to the console are stored in the message buffer during single user mode, and any user can read them later. The use of -a option should be restricted to root user. How-To-Repeat: dmesg -a Fix: --- dmesg.c.dist Wed Feb 21 10:00:26 2001 +++ dmesg.c Wed Feb 21 10:02:11 2001 @@ -56,6 +56,7 @@ #include <unistd.h> #include <vis.h> #include <sys/syslog.h> +#include <sys/types.h> struct nlist nl[] = { #define X_MSGBUF 0 @@ -87,6 +88,10 @@ while ((ch = getopt(argc, argv, "aM:N:")) != -1) switch(ch) { case 'a': + if (getuid() != (uid_t)0) { + fprintf(stderr,"dmesg: must be root to get all data in the message buffer\n"); + exit(1); + } all++; break; case 'M':