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

Commit Message

Philippe Mathieu-Daudé Sept. 10, 2021, 5:06 p.m. UTC

From: Peter Maydell <[e-mail]>

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 <[e-mail]>
Reviewed-by: Viktor Prutyanov <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
Informal T-b tag on
https://lore.kernel.org/qemu-devel/20210909004313.1dadb24e@192.168.1.7/
Tested-by: Viktor Prutyanov <[e-mail]>
---
 contrib/elf2dmp/pdb.c | 4 ++++
 1 file changed, 4 insertions(+)

Comments

Viktor Prutyanov Sept. 10, 2021, 5:13 p.m. UTC | #1

Hi,

On Fri, 10 Sep 2021 19:06:56 +0200
Philippe Mathieu-Daudé <[e-mail]> wrote:

> From: Peter Maydell <[e-mail]>
> 
> 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 <[e-mail]>
> Reviewed-by: Viktor Prutyanov <[e-mail]>
> Message-Id: <[e-mail]>
> Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
> ---
> Informal T-b tag on
> https://lore.kernel.org/qemu-devel/20210909004313.1dadb24e@192.168.1.7/
> Tested-by: Viktor Prutyanov <[e-mail]>
> ---
>  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 +

Tested-by: Viktor Prutyanov <[e-mail]>

Patch

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 +