From c081fa410e7c466df4b3b257e7b974b71fb7f250 Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Wed, 14 Oct 2015 14:37:04 +0200 Subject: [PATCH 2/9] Avoid SIGBUS on mmap failure mmap will fail with SIGBUS if trying to map a non-existent portion of a file. While this should never happen with /dev/mem, it can happen if passing a regular file with option -d. While people should no longer do that, failure gracefully seems better than crashing. So check for the file size before calling mmap. This closes bug #46066: http://savannah.nongnu.org/bugs/?46066 --- CHANGELOG | 6 ++++++ util.c | 21 +++++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/CHANGELOG b/CHANGELOG index 42d815c..aa1c28f 100644 --- a/CHANGELOG +++ b/CHANGELOG @@ -1,3 +1,9 @@ +2015-10-14 Jean Delvare + + * util.c: Avoid SIGBUS on mmap failure. + This fixes Savannah bug #46066: + https://savannah.nongnu.org/bugs/?46066 + 2015-10-01 Roy Franz * dmiopt.c: Add "--no-sysfs" option description to -h output. diff --git a/util.c b/util.c index 8cafe5c..5795d02 100644 --- a/util.c +++ b/util.c @@ -152,6 +152,7 @@ void *mem_chunk(off_t base, size_t len, const char *devmem) void *p; int fd; #ifdef USE_MMAP + struct stat statbuf; off_t mmoffset; void *mmp; #endif @@ -169,6 +170,26 @@ void *mem_chunk(off_t base, size_t len, const char *devmem) } #ifdef USE_MMAP + if (fstat(fd, &statbuf) == -1) + { + fprintf(stderr, "%s: ", devmem); + perror("stat"); + free(p); + return NULL; + } + + /* + * mmap() will fail with SIGBUS if trying to map beyond the end of + * the file. + */ + if (S_ISREG(statbuf.st_mode) && base + (off_t)len > statbuf.st_size) + { + fprintf(stderr, "mmap: Can't map beyond end of file %s\n", + devmem); + free(p); + return NULL; + } + #ifdef _SC_PAGESIZE mmoffset = base % sysconf(_SC_PAGESIZE); #else -- 2.5.0