Re: [Crash-utility] [PATCH V2] netdump: fix regression for tiny kdump files

Date: Wed, 23 Dec 2020 02:31:24 +0000 From: ??? <zhaoqianli(a)xiaomi.com&gt; To: =?gb2312?B?SEFHSU8gS0FaVUhJVE8oyGPOsqGh0rvIyik=?= <k-hagio-ab(a)nec.com&gt;, "Discussion list for crash utility usage, maintenance and development" <crash-utility(a)redhat.com&gt; Subject: Re: [Crash-utility] [External Mail]RE: [PATCH V2] netdump: fix regression for tiny kdump files Message-ID: <e4cc6f753b2c428d9f0f0c0362567de5(a)xiaomi.com&gt; Content-Type: text/plain; charset="gb2312" Hi, Lianbo > 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) { I agrre with Kazu, if use "size != MIN_NETDUMP_ELF_HEADER_SIZE/SAFE_NETDUMP_ELF_HEADER_SIZE" this issue can not be fixed, size is equal to or more than MIN_NETDUMP_ELF_HEADER_SIZE is valid.

> 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); > } Ok. How about below patch set?

>From 5ec6ac06ba7fd32e96463a54ebc3f733f1054a90 Mon Sep 17 00:00:00 2001 From: Qianli Zhao <zhaoqianli(a)xiaomi.com&gt; Date: Mon, 30 Nov 2020 17:17:32 +0800 Subject: [PATCH] netdump: fix regression for tiny kdump files 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 can lead to crash rejecting raw RAM dumpfiles Fix that by erroring out only if we get less than MIN_NETDUMP_ELF_HEADER_SIZE bytes. Signed-off-by: Qianli Zhao <zhaoqianli(a)xiaomi.com&gt; --- netdump.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/netdump.c b/netdump.c index c76d9dd..ca9b459 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; @@ -134,7 +135,7 @@ is_netdump(char *file, ulong source_query) 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); } @@ -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) { + fprintf(stderr, "%s: file too small!\n", file); + goto bailout; } } -- 2.7.4