From 56fc82c5360cdf0b250b5eb74f38657b0402faa5 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 6 Feb 2009 00:48:02 +0900 Subject: modpost: NOBITS sections may point beyond the end of the file Impact: fix link failure on certain toolchains with specific configs Recent percpu change made x86_64 split .data.init section into three separate segments - data.init, percpu and data.init2. data.init2 gets .data.nosave and .bss.* and is followed by .notes segment. Depending on configuration both segments might contain no data, in which case the tool chain makes the section header to contain offset beyond the end of the file. modpost isn't too happy about it and fails build - as reported by Pawel Dziekonski: Building modules, stage 2. MODPOST 416 modules FATAL: vmlinux is truncated. sechdrs[i].sh_offset=10354688 > sizeof(*hrd)=64 make[1]: *** [__modpost] Error 1 Teach modpost that NOBITS section may point beyond the end of the file and that .modinfo can't be NOBITS. Reported-by: Pawel Dziekonski Signed-off-by: Tejun Heo Signed-off-by: Ingo Molnar --- scripts/mod/modpost.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 88921611b22e..7e62303133dc 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -415,8 +415,9 @@ static int parse_elf(struct elf_info *info, const char *filename) const char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset; const char *secname; + int nobits = sechdrs[i].sh_type == SHT_NOBITS; - if (sechdrs[i].sh_offset > info->size) { + if (!nobits && sechdrs[i].sh_offset > info->size) { fatal("%s is truncated. sechdrs[i].sh_offset=%lu > " "sizeof(*hrd)=%zu\n", filename, (unsigned long)sechdrs[i].sh_offset, @@ -425,6 +426,8 @@ static int parse_elf(struct elf_info *info, const char *filename) } secname = secstrings + sechdrs[i].sh_name; if (strcmp(secname, ".modinfo") == 0) { + if (nobits) + fatal("%s has NOBITS .modinfo\n", filename); info->modinfo = (void *)hdr + sechdrs[i].sh_offset; info->modinfo_len = sechdrs[i].sh_size; } else if (strcmp(secname, "__ksymtab") == 0) -- cgit v1.2.3 From 5d707e9c8ef2a3596ed5c975c6ff05cec890c2b4 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 9 Feb 2009 22:17:39 +0900 Subject: stackprotector: update make rules Impact: no default -fno-stack-protector if stackp is enabled, cleanup Stackprotector make rules had the following problems. * cc support test and warning are scattered across makefile and kernel/panic.c. * -fno-stack-protector was always added regardless of configuration. Update such that cc support test and warning are contained in makefile and -fno-stack-protector is added iff stackp is turned off. While at it, prepare for 32bit support. Signed-off-by: Tejun Heo Signed-off-by: Ingo Molnar --- scripts/gcc-x86_64-has-stack-protector.sh | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'scripts') diff --git a/scripts/gcc-x86_64-has-stack-protector.sh b/scripts/gcc-x86_64-has-stack-protector.sh index 325c0a1b03b6..2d69fcdc5609 100644 --- a/scripts/gcc-x86_64-has-stack-protector.sh +++ b/scripts/gcc-x86_64-has-stack-protector.sh @@ -2,5 +2,7 @@ echo "int foo(void) { char X[200]; return 3; }" | $1 -S -xc -c -O0 -mcmodel=kernel -fstack-protector - -o - 2> /dev/null | grep -q "%gs" if [ "$?" -eq "0" ] ; then - echo $2 + echo y +else + echo n fi -- cgit v1.2.3 From 60a5317ff0f42dd313094b88f809f63041568b08 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Mon, 9 Feb 2009 22:17:40 +0900 Subject: x86: implement x86_32 stack protector Impact: stack protector for x86_32 Implement stack protector for x86_32. GDT entry 28 is used for it. It's set to point to stack_canary-20 and have the length of 24 bytes. CONFIG_CC_STACKPROTECTOR turns off CONFIG_X86_32_LAZY_GS and sets %gs to the stack canary segment on entry. As %gs is otherwise unused by the kernel, the canary can be anywhere. It's defined as a percpu variable. x86_32 exception handlers take register frame on stack directly as struct pt_regs. With -fstack-protector turned on, gcc copies the whole structure after the stack canary and (of course) doesn't copy back on return thus losing all changed. For now, -fno-stack-protector is added to all files which contain those functions. We definitely need something better. Signed-off-by: Tejun Heo Signed-off-by: Ingo Molnar --- scripts/gcc-x86_32-has-stack-protector.sh | 8 ++++++++ 1 file changed, 8 insertions(+) create mode 100644 scripts/gcc-x86_32-has-stack-protector.sh (limited to 'scripts') diff --git a/scripts/gcc-x86_32-has-stack-protector.sh b/scripts/gcc-x86_32-has-stack-protector.sh new file mode 100644 index 000000000000..4fdf6ce1b062 --- /dev/null +++ b/scripts/gcc-x86_32-has-stack-protector.sh @@ -0,0 +1,8 @@ +#!/bin/sh + +echo "int foo(void) { char X[200]; return 3; }" | $1 -S -xc -c -O0 -fstack-protector - -o - 2> /dev/null | grep -q "%gs" +if [ "$?" -eq "0" ] ; then + echo y +else + echo n +fi -- cgit v1.2.3 From ebd9026d9f8499abc60d82d949bd37f88fe34a41 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Wed, 11 Feb 2009 12:17:29 +0100 Subject: stackprotector: fix multi-word cross-builds Stackprotector builds were failing if CROSS_COMPILER was more than a single world (such as when distcc was used) - because the check scripts used $1 instead of $*. Signed-off-by: Ingo Molnar --- scripts/gcc-x86_32-has-stack-protector.sh | 2 +- scripts/gcc-x86_64-has-stack-protector.sh | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'scripts') diff --git a/scripts/gcc-x86_32-has-stack-protector.sh b/scripts/gcc-x86_32-has-stack-protector.sh index 4fdf6ce1b062..29493dc4528d 100644 --- a/scripts/gcc-x86_32-has-stack-protector.sh +++ b/scripts/gcc-x86_32-has-stack-protector.sh @@ -1,6 +1,6 @@ #!/bin/sh -echo "int foo(void) { char X[200]; return 3; }" | $1 -S -xc -c -O0 -fstack-protector - -o - 2> /dev/null | grep -q "%gs" +echo "int foo(void) { char X[200]; return 3; }" | $* -S -xc -c -O0 -fstack-protector - -o - 2> /dev/null | grep -q "%gs" if [ "$?" -eq "0" ] ; then echo y else diff --git a/scripts/gcc-x86_64-has-stack-protector.sh b/scripts/gcc-x86_64-has-stack-protector.sh index 2d69fcdc5609..afaec618b395 100644 --- a/scripts/gcc-x86_64-has-stack-protector.sh +++ b/scripts/gcc-x86_64-has-stack-protector.sh @@ -1,6 +1,6 @@ #!/bin/sh -echo "int foo(void) { char X[200]; return 3; }" | $1 -S -xc -c -O0 -mcmodel=kernel -fstack-protector - -o - 2> /dev/null | grep -q "%gs" +echo "int foo(void) { char X[200]; return 3; }" | $* -S -xc -c -O0 -mcmodel=kernel -fstack-protector - -o - 2> /dev/null | grep -q "%gs" if [ "$?" -eq "0" ] ; then echo y else -- cgit v1.2.3