Hi, Qianli
Thanks for the patch.
在 2020年12月01日 14:45, crash-utility-requ...@redhat.com 写道:
> Date: Tue, 1 Dec 2020 10:56:02 +0800
> From: Qianli Zhao <zhaoqianlig...@gmail.com>
> To: crash-utility@redhat.com, mini...@grsecurity.net
> Subject: [Crash-utility] [PATCH V2] netdump: fix regression for tiny
> kdump files
> Message-ID:
> <1606791362-5604-1-git-send-email-zhaoqianlig...@gmail.com>
> Content-Type: text/plain; charset="US-ASCII"
>
> From: Qianli Zhao <zhaoqia...@xiaomi.com>
>
> Commit f42db6a33f0e ("Support core files with "unusual" layout")
> increased the minimal file size from MIN_NETDUMP_ELF_HEADER_SIZE to
> SAFE_NETDUMP_ELF_HEADER_SIZE which lead to crash rejecting very
> small kdump files.
>
Good findings.
> Fix that by erroring out only if we get less than
> MIN_NETDUMP_ELF_HEADER_SIZE bytes.
>
> Signed-off-by: Qianli Zhao <zhaoqia...@xiaomi.com>
> ---
> - Update commit message
> - Add more accurate judgment of read() return value
> ---
> netdump.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/netdump.c b/netdump.c
> index c76d9dd..9a36931 100644
> --- a/netdump.c
> +++ b/netdump.c
> @@ -119,7 +119,8 @@ is_netdump(char *file, ulong source_query)
> Elf64_Phdr *load64;
> char *eheader, *sect0;
> char buf[BUFSIZE];
> - size_t size, len, tot;
> + ssize_t size;
> + size_t len, tot;
> Elf32_Off offset32;
> Elf64_Off offset64;
> ulong format;
> @@ -142,10 +143,14 @@ is_netdump(char *file, ulong source_query)
> if (!read_flattened_format(fd, 0, eheader, size))
> goto bailout;
> } else {
> - if (read(fd, eheader, size) != size) {
> + size = read(fd, eheader, size);
> + if (size < 0) {
> sprintf(buf, "%s: ELF header read", file);
> perror(buf);
> goto bailout;
> + } else if (size < MIN_NETDUMP_ELF_HEADER_SIZE) {
For the checking condition, I would recommend using the following methods, what
do you think?
+ if (size != SAFE_NETDUMP_ELF_HEADER_SIZE &&
+ size != MIN_NETDUMP_ELF_HEADER_SIZE) {
sprintf(buf, "%s: ELF header read", file);
perror(buf);
goto bailout;
}
In addition, would you mind updating another error output in the is_netdump()?
For example:
size = SAFE_NETDUMP_ELF_HEADER_SIZE;
if ((eheader = (char *)malloc(size)) == NULL) {
- fprintf(stderr, "cannot malloc minimum ELF header buffer\n");
+ fprintf(stderr, "cannot malloc ELF header buffer\n");
clean_exit(1);
}
Thanks.
Lianbo
> + fprintf(stderr, "%s: file too small!\n", file);
> + goto bailout;
> }
> }
>
> -- 2.7.4
--
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