Add function sanity_check_page_desc(). This sanity checks an given
entry of page descriptor table based on the conditions that are
expected to hold in each filed, i.e.:
- offset must be smaller than a file size of dump file.
- size must not be 0 and equal to or smaller than a block size.
- If size is equal to a block size, it means the page is not
compressed and so flags must be 0.
- If size is smaller than a block size, it means the page is
compressed and so flags must hold any of compression flags.
- page_flags must constantly be 0 because this field is unused.
This will be later used to validate a single entry of page descriptor
table when it is read in cache_page() and to validate a whole part of
page descriptor table when --validate_kdump_headers command-line
option is specified.
---
diskdump.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/diskdump.c b/diskdump.c
index a495120..2d2cf97 100644
--- a/diskdump.c
+++ b/diskdump.c
@@ -92,6 +92,7 @@ static void dump_note_offsets(FILE *);
static char *vmcoreinfo_read_string(const char *);
static void diskdump_get_osrelease(void);
static int valid_note_address(unsigned char *);
+static int sanity_check_page_desc(page_desc_t *);
/* For split dumpfile */
static struct diskdump_data **dd_list = NULL;
@@ -3134,3 +3135,13 @@ out:
FREEBUF(zram_buf);
return len;
}
+
+static int sanity_check_page_desc(page_desc_t *pd)
+{
+ return pd->offset < dd->stat.st_size &&
+ pd->size &&
+ pd->size <= dd->block_size &&
+ ((pd->size == dd->block_size && pd->flags == 0) ||
+ (pd->size < dd->block_size && pd->flags & (DUMP_DH_COMPRESSED_ZLIB|DUMP_DH_COMPRESSED_LZO|DUMP_DH_COMPRESSED_SNAPPY|DUMP_DH_COMPRESSED_ZSTD))) &&
+ pd->page_flags == 0;
+}
--
2.43.1
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