[PATCH v2 2/2] elf2dmp: Fail cleanly if PDB file specifies zero block_size

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

From: Peter Maydell <peter.maydell@linaro.org>

Coverity points out that if the PDB file we're trying to read
has a header specifying a block_size of zero then we will
end up trying to divide by zero in pdb_ds_read_file().
Check for this and fail cleanly instead.

Fixes: Coverity CID 1458869
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
Message-Id: <20210901143910.17112-3-peter.maydell@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
Informal T-b tag on
https://lore.kernel.org/qemu-devel/20210909004313.1dadb24e@192.168.1.7/
Tested-by: Viktor Prutyanov <viktor.prutyanov@phystech.edu>
---
 contrib/elf2dmp/pdb.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/contrib/elf2dmp/pdb.c b/contrib/elf2dmp/pdb.c
index b3a65470680..adcfa7e154c 100644
--- a/contrib/elf2dmp/pdb.c
+++ b/contrib/elf2dmp/pdb.c
@@ -215,6 +215,10 @@ out_symbols:
 
 static int pdb_reader_ds_init(struct pdb_reader *r, PDB_DS_HEADER *hdr)
 {
+    if (hdr->block_size == 0) {
+        return 1;
+    }
+
     memset(r->file_used, 0, sizeof(r->file_used));
     r->ds.header = hdr;
     r->ds.toc = pdb_ds_read(hdr, (uint32_t *)((uint8_t *)hdr +
-- 
2.31.1