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

From: Qianli Zhao <zhaoqianli(a)xiaomi.com&gt; 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. 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; --- - 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) { + fprintf(stderr, "%s: file too small!\n", file); + goto bailout; } }