diff --git a/ASLR-fix-stack-randomization-on-64-bit-systems.patch b/ASLR-fix-stack-randomization-on-64-bit-systems.patch new file mode 100644 index 0000000..b382815 --- /dev/null +++ b/ASLR-fix-stack-randomization-on-64-bit-systems.patch @@ -0,0 +1,104 @@ +From: Hector Marco-Gisbert +Date: Sat, 14 Feb 2015 09:33:50 -0800 +Subject: [PATCH] ASLR: fix stack randomization on 64-bit systems + +The issue is that the stack for processes is not properly randomized on 64 bit +architectures due to an integer overflow. + +The affected function is randomize_stack_top() in file "fs/binfmt_elf.c": + +static unsigned long randomize_stack_top(unsigned long stack_top) +{ + unsigned int random_variable = 0; + + if ((current->flags & PF_RANDOMIZE) && + !(current->personality & ADDR_NO_RANDOMIZE)) { + random_variable = get_random_int() & STACK_RND_MASK; + random_variable <<= PAGE_SHIFT; + } + return PAGE_ALIGN(stack_top) + random_variable; + return PAGE_ALIGN(stack_top) - random_variable; +} + +Note that, it declares the "random_variable" variable as "unsigned int". Since +the result of the shifting operation between STACK_RND_MASK (which is +0x3fffff on x86_64, 22 bits) and PAGE_SHIFT (which is 12 on x86_64): + +random_variable <<= PAGE_SHIFT; + +then the two leftmost bits are dropped when storing the result in the +"random_variable". This variable shall be at least 34 bits long to hold the +(22+12) result. + +These two dropped bits have an impact on the entropy of process stack. +Concretely, the total stack entropy is reduced by four: from 2^28 to 2^30 (One +fourth of expected entropy). + +This patch restores back the entropy by correcting the types involved in the +operations in the functions randomize_stack_top() and stack_maxrandom_size(). + +The successful fix can be tested with: +$ for i in `seq 1 10`; do cat /proc/self/maps | grep stack; done +7ffeda566000-7ffeda587000 rw-p 00000000 00:00 0 [stack] +7fff5a332000-7fff5a353000 rw-p 00000000 00:00 0 [stack] +7ffcdb7a1000-7ffcdb7c2000 rw-p 00000000 00:00 0 [stack] +7ffd5e2c4000-7ffd5e2e5000 rw-p 00000000 00:00 0 [stack] +... + +Once corrected, the leading bytes should be between 7ffc and 7fff, rather +than always being 7fff. + +CVE-2015-1593 + +Signed-off-by: Hector Marco-Gisbert +Signed-off-by: Ismael Ripoll +[kees: rebase, fix 80 char, clean up commit message, add test example, cve] +Signed-off-by: Kees Cook +Cc: stable@vger.kernel.org +--- + arch/x86/mm/mmap.c | 6 +++--- + fs/binfmt_elf.c | 5 +++-- + 2 files changed, 6 insertions(+), 5 deletions(-) + +diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c +index 919b91205cd4..df4552bd239e 100644 +--- a/arch/x86/mm/mmap.c ++++ b/arch/x86/mm/mmap.c +@@ -35,12 +35,12 @@ struct va_alignment __read_mostly va_align = { + .flags = -1, + }; + +-static unsigned int stack_maxrandom_size(void) ++static unsigned long stack_maxrandom_size(void) + { +- unsigned int max = 0; ++ unsigned long max = 0; + if ((current->flags & PF_RANDOMIZE) && + !(current->personality & ADDR_NO_RANDOMIZE)) { +- max = ((-1U) & STACK_RND_MASK) << PAGE_SHIFT; ++ max = ((-1UL) & STACK_RND_MASK) << PAGE_SHIFT; + } + + return max; +diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c +index 02b16910f4c9..995986b8e36b 100644 +--- a/fs/binfmt_elf.c ++++ b/fs/binfmt_elf.c +@@ -645,11 +645,12 @@ out: + + static unsigned long randomize_stack_top(unsigned long stack_top) + { +- unsigned int random_variable = 0; ++ unsigned long random_variable = 0; + + if ((current->flags & PF_RANDOMIZE) && + !(current->personality & ADDR_NO_RANDOMIZE)) { +- random_variable = get_random_int() & STACK_RND_MASK; ++ random_variable = (unsigned long) get_random_int(); ++ random_variable &= STACK_RND_MASK; + random_variable <<= PAGE_SHIFT; + } + #ifdef CONFIG_STACK_GROWSUP +-- +2.1.0 + diff --git a/kernel.spec b/kernel.spec index b36b1e1..78e8c3b 100644 --- a/kernel.spec +++ b/kernel.spec @@ -617,6 +617,9 @@ Patch26133: ntp-Fixup-adjtimex-freq-validation-on-32bit-systems.patch Patch26134: perf-tools-Define-_GNU_SOURCE-on-pthread_attr_setaff.patch +#CVE-2015-1593 rhbz 1192519 1192520 +Patch26135: ASLR-fix-stack-randomization-on-64-bit-systems.patch + # git clone ssh://git.fedorahosted.org/git/kernel-arm64.git, git diff master...devel Patch30000: kernel-arm64.patch @@ -1343,6 +1346,9 @@ ApplyPatch ntp-Fixup-adjtimex-freq-validation-on-32bit-systems.patch ApplyPatch perf-tools-Define-_GNU_SOURCE-on-pthread_attr_setaff.patch +#CVE-2015-1593 rhbz 1192519 1192520 +ApplyPatch ASLR-fix-stack-randomization-on-64-bit-systems.patch + %if 0%{?aarch64patches} ApplyPatch kernel-arm64.patch %ifnarch aarch64 # this is stupid, but i want to notice before secondary koji does. @@ -2209,6 +2215,9 @@ fi # ||----w | # || || %changelog +* Mon Feb 16 2015 Josh Boyer +- CVE-2015-1593 stack ASLR integer overflow (rhbz 1192519 1192520) + * Mon Feb 16 2015 Peter Robinson - Minor updates for ARMv7/ARM64