Re: [Crash-utility] [PATCH] Add file size check at the beginning
Bernhard Walle wrote:
I had a bug report because of a truncated vmcore file. The error
message just
was
crash: read error: kernel virtual address: ffff8107f3c3a6c0 type: "cpu_pda
entry"
which is very unclear for a 'normal' user. This patch adds checking of the file
size according to the ELF header at the beginning so that a clear error message
can be printed.
Please consider adding the patch to crash.
I'm hesitant about is_netdump() simply returning FALSE, and therefore
essentially saying: "this isn't a netdump or kdump file -- go check
whether it's some other dumpfile type".
And what if the dumpfile is short, but still usable? We sure
have seen a lot of real netdump files (i.e. not kdumps) that
have been truncated, but still usable.
I understand the concern about the read error message, but maybe
a better way to do it would be to just issue a WARNING message?
Dave
Signed-off-by: Bernhard Walle <bwalle(a)suse.de>
---
defs.h | 1 +
netdump.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 45 insertions(+)
--- a/defs.h
+++ b/defs.h
@@ -16,6 +16,7 @@
* GNU General Public License for more details.
*/
+#define _LARGEFILE64_SOURCE 1 /* stat64() */
#ifndef GDB_COMMON
#include <stdio.h>
--- a/netdump.c
+++ b/netdump.c
@@ -33,6 +33,47 @@ static physaddr_t xen_kdump_p2m(physaddr
#define ELFREAD 0
#define MIN_PAGE_SIZE (4096)
+
+
+static int
+check_netdump_filesize(char *file)
+{
+ uint64_t max_file_offset = 0;
+ struct pt_load_segment *pls;
+ struct stat64 stat;
+ int i, ret;
+
+
+ /* find the maximum file offset */
+ for (i = 0; i < nd->num_pt_load_segments; i++) {
+ uint64_t end, size;
+
+ pls = &nd->pt_load_segments[i];
+
+ size = pls->phys_end - pls->phys_start;
+ end = pls->file_offset + size;
+
+ if (end > max_file_offset)
+ max_file_offset = end;
+ }
+
+ ret = stat64(file, &stat);
+ if (ret < 0) {
+ fprintf(stderr, "Cannot stat64 on %s: %s\n", file,
+ strerror(errno));
+ return FALSE;
+ }
+
+ if (max_file_offset > stat.st_size) {
+ fprintf(stderr, "File %s is too short:\n"
+ "Must be %lld bytes but is only "
+ "%lld bytes long.\n",
+ file, max_file_offset, stat.st_size);
+ return FALSE;
+ }
+
+ return TRUE;
+}
/*
* Determine whether a file is a netdump/diskdump/kdump creation,
@@ -267,6 +308,9 @@ is_netdump(char *file, ulong source_quer
if (CRASHDEBUG(1))
netdump_memory_dump(fp);
+ if (!check_netdump_filesize(file))
+ return FALSE;
+
return nd->header_size;
bailout:
--
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