|
 |
5eed2e |
commit 68d120b30af5e930afafed81e79712af3c1a278c
|
|
|
5eed2e |
Author: Philipp Rudo <prudo@redhat.com>
|
|
|
5eed2e |
Date: Mon Mar 14 17:04:31 2022 +0100
|
|
|
5eed2e |
|
|
|
5eed2e |
[PATCH v2 3/3] use cycle detection when parsing the prink log_buf
|
|
|
5eed2e |
|
|
|
5eed2e |
The old printk mechanism (> v3.5.0 and < v5.10.0) had a fixed size
|
|
|
5eed2e |
buffer (log_buf) that contains all messages. The location for the next
|
|
|
5eed2e |
message is stored in log_next_idx. In case the log_buf runs full
|
|
|
5eed2e |
log_next_idx wraps around and starts overwriting old messages at the
|
|
|
5eed2e |
beginning of the buffer. The wraparound is denoted by a message with
|
|
|
5eed2e |
msg->len == 0.
|
|
|
5eed2e |
|
|
|
5eed2e |
Following the behavior described above blindly in makedumpfile is
|
|
|
5eed2e |
dangerous as e.g. a memory corruption could overwrite (parts of) the
|
|
|
5eed2e |
log_buf. If the corruption adds a message with msg->len == 0 this leads
|
|
|
5eed2e |
to an endless loop when dumping the dmesg with makedumpfile appending
|
|
|
5eed2e |
the messages up to the corruption over and over again to the output file
|
|
|
5eed2e |
until file system is full. Fix this by using cycle detection and aboard
|
|
|
5eed2e |
once one is detected.
|
|
|
5eed2e |
|
|
|
5eed2e |
While at it also verify that the index is within the log_buf and thus
|
|
|
5eed2e |
guard against corruptions with msg->len != 0.
|
|
|
5eed2e |
|
|
|
5eed2e |
Reported-by: Audra Mitchell <aubaker@redhat.com>
|
|
|
5eed2e |
Suggested-by: Dave Wysochanski <dwysocha@redhat.com>
|
|
|
5eed2e |
Signed-off-by: Philipp Rudo <prudo@redhat.com>
|
|
|
5eed2e |
Reviewed-and-tested-by: Dave Wysochanski <dwysocha@redhat.com>
|
|
|
5eed2e |
|
|
|
5eed2e |
diff --git a/makedumpfile-1.7.0/makedumpfile.c b/makedumpfile-1.7.0/makedumpfile.c
|
|
|
5eed2e |
index e72dba219eec198ec865045562f39a14b5a092eb..2b94446b8f2ad513da060e15821544ae32e1a2c6 100644
|
|
|
5eed2e |
--- a/makedumpfile-1.7.0/makedumpfile.c
|
|
|
5eed2e |
+++ b/makedumpfile-1.7.0/makedumpfile.c
|
|
|
5eed2e |
@@ -15,6 +15,7 @@
|
|
|
5eed2e |
*/
|
|
|
5eed2e |
#include "makedumpfile.h"
|
|
|
5eed2e |
#include "print_info.h"
|
|
|
5eed2e |
+#include "detect_cycle.h"
|
|
|
5eed2e |
#include "dwarf_info.h"
|
|
|
5eed2e |
#include "elf_info.h"
|
|
|
5eed2e |
#include "erase_info.h"
|
|
|
5eed2e |
@@ -5526,10 +5527,11 @@ dump_dmesg()
|
|
|
5eed2e |
unsigned long index, log_buf, log_end;
|
|
|
5eed2e |
unsigned int log_first_idx, log_next_idx;
|
|
|
5eed2e |
unsigned long long first_idx_sym;
|
|
|
5eed2e |
+ struct detect_cycle *dc = NULL;
|
|
|
5eed2e |
unsigned long log_end_2_6_24;
|
|
|
5eed2e |
unsigned log_end_2_6_25;
|
|
|
5eed2e |
char *log_buffer = NULL, *log_ptr = NULL;
|
|
|
5eed2e |
- char *ptr;
|
|
|
5eed2e |
+ char *ptr, *next_ptr;
|
|
|
5eed2e |
|
|
|
5eed2e |
/*
|
|
|
5eed2e |
* log_end has been changed to "unsigned" since linux-2.6.25.
|
|
|
5eed2e |
@@ -5677,12 +5679,55 @@ dump_dmesg()
|
|
|
5eed2e |
goto out;
|
|
|
5eed2e |
}
|
|
|
5eed2e |
ptr = log_buffer + log_first_idx;
|
|
|
5eed2e |
+ dc = dc_init(ptr, log_buffer, log_next);
|
|
|
5eed2e |
while (ptr != log_buffer + log_next_idx) {
|
|
|
5eed2e |
log_ptr = log_from_ptr(ptr, log_buffer);
|
|
|
5eed2e |
if (!dump_log_entry(log_ptr, info->fd_dumpfile,
|
|
|
5eed2e |
info->name_dumpfile))
|
|
|
5eed2e |
goto out;
|
|
|
5eed2e |
ptr = log_next(ptr, log_buffer);
|
|
|
5eed2e |
+ if (dc_next(dc, (void **) &next_ptr)) {
|
|
|
5eed2e |
+ unsigned long len;
|
|
|
5eed2e |
+ int in_cycle;
|
|
|
5eed2e |
+ char *first;
|
|
|
5eed2e |
+
|
|
|
5eed2e |
+ /* Clear everything we have already written... */
|
|
|
5eed2e |
+ ftruncate(info->fd_dumpfile, 0);
|
|
|
5eed2e |
+ lseek(info->fd_dumpfile, 0, SEEK_SET);
|
|
|
5eed2e |
+
|
|
|
5eed2e |
+ /* ...and only write up to the corruption. */
|
|
|
5eed2e |
+ dc_find_start(dc, (void **) &first, &len;;
|
|
|
5eed2e |
+ ptr = log_buffer + log_first_idx;
|
|
|
5eed2e |
+ in_cycle = FALSE;
|
|
|
5eed2e |
+ while (len) {
|
|
|
5eed2e |
+ log_ptr = log_from_ptr(ptr, log_buffer);
|
|
|
5eed2e |
+ if (!dump_log_entry(log_ptr,
|
|
|
5eed2e |
+ info->fd_dumpfile,
|
|
|
5eed2e |
+ info->name_dumpfile))
|
|
|
5eed2e |
+ goto out;
|
|
|
5eed2e |
+ ptr = log_next(ptr, log_buffer);
|
|
|
5eed2e |
+
|
|
|
5eed2e |
+ if (log_ptr == first)
|
|
|
5eed2e |
+ in_cycle = TRUE;
|
|
|
5eed2e |
+
|
|
|
5eed2e |
+ if (in_cycle)
|
|
|
5eed2e |
+ len--;
|
|
|
5eed2e |
+ }
|
|
|
5eed2e |
+ ERRMSG("Cycle when parsing dmesg detected.\n");
|
|
|
5eed2e |
+ ERRMSG("The printk log_buf is most likely corrupted.\n");
|
|
|
5eed2e |
+ ERRMSG("log_buf = 0x%lx, idx = 0x%lx\n", log_buf, ptr - log_buffer);
|
|
|
5eed2e |
+ close_files_for_creating_dumpfile();
|
|
|
5eed2e |
+ goto out;
|
|
|
5eed2e |
+ }
|
|
|
5eed2e |
+ if (next_ptr < log_buffer ||
|
|
|
5eed2e |
+ next_ptr > log_buffer + log_buf_len - SIZE(printk_log)) {
|
|
|
5eed2e |
+ ERRMSG("Index outside log_buf detected.\n");
|
|
|
5eed2e |
+ ERRMSG("The printk log_buf is most likely corrupted.\n");
|
|
|
5eed2e |
+ ERRMSG("log_buf = 0x%lx, idx = 0x%lx\n", log_buf, ptr - log_buffer);
|
|
|
5eed2e |
+ close_files_for_creating_dumpfile();
|
|
|
5eed2e |
+ goto out;
|
|
|
5eed2e |
+ }
|
|
|
5eed2e |
+ ptr = next_ptr;
|
|
|
5eed2e |
}
|
|
|
5eed2e |
if (!close_files_for_creating_dumpfile())
|
|
|
5eed2e |
goto out;
|
|
|
5eed2e |
@@ -5692,6 +5737,7 @@ dump_dmesg()
|
|
|
5eed2e |
out:
|
|
|
5eed2e |
if (log_buffer)
|
|
|
5eed2e |
free(log_buffer);
|
|
|
5eed2e |
+ free(dc);
|
|
|
5eed2e |
|
|
|
5eed2e |
return ret;
|
|
|
5eed2e |
}
|