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authorJan Kratochvil <jan.kratochvil@redhat.com>2014-02-21 18:39:40 +0100
committerJan Kratochvil <jan.kratochvil@redhat.com>2014-02-21 18:39:40 +0100
commit184cd07257b5dd74a4eb9f6857fc6dd785f53492 (patch)
tree9821fa0b3d4983f24cfe26269caa8b152beca499 /gdb
parentdcf893b581c440902d68a0095967acd4ae7ae8d1 (diff)
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Fix crash on process name "(sd-pam)" (PR 16594).
info os processes -fsanitize=address error https://sourceware.org/bugzilla/show_bug.cgi?id=16594 info os processes ================================================================= ==5795== ERROR: AddressSanitizer: heap-use-after-free on address 0x600600214974 at pc 0x757a92 bp 0x7fff95dd9f00 sp 0x7fff95dd9ef0 READ of size 4 at 0x600600214974 thread T0 #0 0x757a91 in get_cores_used_by_process (.../gdb/gdb+0x757a91) At least Fedora 20 has process(es): 6678 ? Ss 0:00 /usr/lib/systemd/systemd --user 6680 ? S 0:00 \_ (sd-pam) and GDB "info os processes" crashes on it as /proc/6680/stat contains: 6680 ((sd-pam)) S 6678 6678 6678 0 -1 1077961024 33 0 0 0 0 0 0 0 20 0 1 0 18568 73768960 120 18446744073709551615 1 1 0 0 0 0 0 4096 0 18446744073709551615 0 0 17 6 0 0 0 0 0 0 0 0 0 0 0 0 0 and GDB fails to find the proper end of the process name "((sd-pam))". Therefore it reads core number off-by-one (it reads 17 instead of 6) and overruns the array. (1) Make the process name parsing more foolproof. (2) Do not trust the parsed number from /proc/PID/stat and verify it against the array size. I noticed that 'ps' gets this right, so I've peeked at its sources, and it just looks for the first ')' starting at the end. https://gitorious.org/procps/procps/source/dc072aced7250fed9b01fb05f0d672678752a63e:proc/readproc.c Look for stat2proc. Given ps does that, I believe the kernel won't ever be changed in a way that would break it. So it sounds like could do strrchr from the end of stat just as well without worry, which is simpler. gdb/ 2014-02-21 Jan Kratochvil <jan.kratochvil@redhat.com> PR gdb/16594 * common/linux-osdata.c (linux_common_core_of_thread): Find the end of process name. (get_cores_used_by_process): New parameter num_cores, use it. (linux_xfer_osdata_processes): Pass num_cores to it. * linux-tdep.c (linux_info_proc, linux_fill_prpsinfo): Find the end of process name. Message-ID: <20140217212826.GA15080@host2.jankratochvil.net>
Diffstat (limited to 'gdb')
-rw-r--r--gdb/ChangeLog10
-rw-r--r--gdb/common/linux-osdata.c16
-rw-r--r--gdb/linux-tdep.c18
3 files changed, 27 insertions, 17 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 9406d76..f97c5fe 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,13 @@
+2014-02-21 Jan Kratochvil <jan.kratochvil@redhat.com>
+
+ PR gdb/16594
+ * common/linux-osdata.c (linux_common_core_of_thread): Find the end of
+ process name.
+ (get_cores_used_by_process): New parameter num_cores, use it.
+ (linux_xfer_osdata_processes): Pass num_cores to it.
+ * linux-tdep.c (linux_info_proc, linux_fill_prpsinfo): Find the end of
+ process name.
+
2014-02-21 Andreas Arnez <arnez@vnet.linux.ibm.com>
* target.c (memory_xfer_partial): Fix length arg in call to
diff --git a/gdb/common/linux-osdata.c b/gdb/common/linux-osdata.c
index 805850c..dae637b 100644
--- a/gdb/common/linux-osdata.c
+++ b/gdb/common/linux-osdata.c
@@ -96,11 +96,8 @@ linux_common_core_of_thread (ptid_t ptid)
}
}
- p = strchr (content, '(');
-
- /* Skip ")". */
- if (p != NULL)
- p = strchr (p, ')');
+ /* ps command also relies on no trailing fields ever contain ')'. */
+ p = strrchr (content, ')');
if (p != NULL)
p++;
@@ -258,11 +255,10 @@ get_process_owner (uid_t *owner, PID_T pid)
}
/* Find the CPU cores used by process PID and return them in CORES.
- CORES points to an array of at least sysconf(_SC_NPROCESSOR_ONLN)
- elements. */
+ CORES points to an array of NUM_CORES elements. */
static int
-get_cores_used_by_process (PID_T pid, int *cores)
+get_cores_used_by_process (PID_T pid, int *cores, const int num_cores)
{
char taskdir[sizeof ("/proc/") + MAX_PID_T_STRLEN + sizeof ("/task") - 1];
DIR *dir;
@@ -286,7 +282,7 @@ get_cores_used_by_process (PID_T pid, int *cores)
core = linux_common_core_of_thread (ptid_build ((pid_t) pid,
(pid_t) tid, 0));
- if (core >= 0)
+ if (core >= 0 && core < num_cores)
{
++cores[core];
++task_count;
@@ -350,7 +346,7 @@ linux_xfer_osdata_processes (gdb_byte *readbuf,
/* Find CPU cores used by the process. */
cores = (int *) xcalloc (num_cores, sizeof (int));
- task_count = get_cores_used_by_process (pid, cores);
+ task_count = get_cores_used_by_process (pid, cores, num_cores);
cores_str = (char *) xcalloc (task_count, sizeof ("4294967295") + 1);
for (i = 0; i < num_cores && task_count > 0; ++i)
diff --git a/gdb/linux-tdep.c b/gdb/linux-tdep.c
index bd1e5a2..c10b8ee 100644
--- a/gdb/linux-tdep.c
+++ b/gdb/linux-tdep.c
@@ -476,7 +476,9 @@ linux_info_proc (struct gdbarch *gdbarch, char *args,
p = skip_spaces_const (p);
if (*p == '(')
{
- const char *ep = strchr (p, ')');
+ /* ps command also relies on no trailing fields
+ ever contain ')'. */
+ const char *ep = strrchr (p, ')');
if (ep != NULL)
{
printf_filtered ("Exec file: %.*s\n",
@@ -1331,12 +1333,14 @@ linux_fill_prpsinfo (struct elf_internal_linux_prpsinfo *p)
proc_stat = skip_spaces (proc_stat);
- /* Getting rid of the executable name, since we already have it. We
- know that this name will be in parentheses, so we can safely look
- for the close-paren. */
- while (*proc_stat != ')')
- ++proc_stat;
- ++proc_stat;
+ /* ps command also relies on no trailing fields ever contain ')'. */
+ proc_stat = strrchr (proc_stat, ')');
+ if (proc_stat == NULL)
+ {
+ do_cleanups (c);
+ return 1;
+ }
+ proc_stat++;
proc_stat = skip_spaces (proc_stat);