diff --git a/kernel.spec b/kernel.spec index 8d7f1de..e72bcb2 100644 --- a/kernel.spec +++ b/kernel.spec @@ -62,7 +62,7 @@ Summary: The Linux kernel # For non-released -rc kernels, this will be appended after the rcX and # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3" # -%global baserelease 1 +%global baserelease 2 %global fedora_build %{baserelease} # base_sublevel is the kernel version we're starting with and patching @@ -745,6 +745,9 @@ Patch21247: ath9k_rx_dma_stop_check.patch #rhbz 910126 Patch21249: pstore-Create-a-convenient-mount-point-for-pstore.patch +#rhbz 906309 910848 CVE-2013-0228 +Patch21260: xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch + Patch22000: weird-root-dentry-name-debug.patch #selinux ptrace child permissions @@ -1455,6 +1458,9 @@ ApplyPatch ath9k_rx_dma_stop_check.patch #rhbz 910126 ApplyPatch pstore-Create-a-convenient-mount-point-for-pstore.patch +#rhbz 906309 910848 CVE-2013-0228 +ApplyPatch xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch + # END OF PATCH APPLICATIONS %endif @@ -2310,6 +2316,9 @@ fi # ||----w | # || || %changelog +* Thu Feb 14 2013 Josh Boyer +- CVE-2013-0228 xen: xen_iret() invalid %ds local DoS (rhbz 910848 906309) + * Wed Feb 13 2013 Peter Robinson - Disable tegra30 diff --git a/xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch b/xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch new file mode 100644 index 0000000..d3b2b56 --- /dev/null +++ b/xen-dont-assume-ds-is-usable-in-xen_iret-for-32-bit-PVOPS.patch @@ -0,0 +1,131 @@ +From 13d2b4d11d69a92574a55bfd985cfb0ca77aebdc Mon Sep 17 00:00:00 2001 +From: Jan Beulich +Date: Thu, 24 Jan 2013 13:11:10 +0000 +Subject: [PATCH] x86/xen: don't assume %ds is usable in xen_iret for 32-bit + PVOPS. + +This fixes CVE-2013-0228 / XSA-42 + +Drew Jones while working on CVE-2013-0190 found that that unprivileged guest user +in 32bit PV guest can use to crash the > guest with the panic like this: + +------------- +general protection fault: 0000 [#1] SMP +last sysfs file: /sys/devices/vbd-51712/block/xvda/dev +Modules linked in: sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 +iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 +xt_state nf_conntrack ip6table_filter ip6_tables ipv6 xen_netfront ext4 +mbcache jbd2 xen_blkfront dm_mirror dm_region_hash dm_log dm_mod [last +unloaded: scsi_wait_scan] + +Pid: 1250, comm: r Not tainted 2.6.32-356.el6.i686 #1 +EIP: 0061:[] EFLAGS: 00010086 CPU: 0 +EIP is at xen_iret+0x12/0x2b +EAX: eb8d0000 EBX: 00000001 ECX: 08049860 EDX: 00000010 +ESI: 00000000 EDI: 003d0f00 EBP: b77f8388 ESP: eb8d1fe0 + DS: 0000 ES: 007b FS: 0000 GS: 00e0 SS: 0069 +Process r (pid: 1250, ti=eb8d0000 task=c2953550 task.ti=eb8d0000) +Stack: + 00000000 0027f416 00000073 00000206 b77f8364 0000007b 00000000 00000000 +Call Trace: +Code: c3 8b 44 24 18 81 4c 24 38 00 02 00 00 8d 64 24 30 e9 03 00 00 00 +8d 76 00 f7 44 24 08 00 00 02 80 75 33 50 b8 00 e0 ff ff 21 e0 <8b> 40 +10 8b 04 85 a0 f6 ab c0 8b 80 0c b0 b3 c0 f6 44 24 0d 02 +EIP: [] xen_iret+0x12/0x2b SS:ESP 0069:eb8d1fe0 +general protection fault: 0000 [#2] +---[ end trace ab0d29a492dcd330 ]--- +Kernel panic - not syncing: Fatal exception +Pid: 1250, comm: r Tainted: G D --------------- +2.6.32-356.el6.i686 #1 +Call Trace: + [] ? panic+0x6e/0x122 + [] ? oops_end+0xbc/0xd0 + [] ? do_general_protection+0x0/0x210 + [] ? error_code+0x73/ +------------- + +Petr says: " + I've analysed the bug and I think that xen_iret() cannot cope with + mangled DS, in this case zeroed out (null selector/descriptor) by either + xen_failsafe_callback() or RESTORE_REGS because the corresponding LDT + entry was invalidated by the reproducer. " + +Jan took a look at the preliminary patch and came up a fix that solves +this problem: + +"This code gets called after all registers other than those handled by +IRET got already restored, hence a null selector in %ds or a non-null +one that got loaded from a code or read-only data descriptor would +cause a kernel mode fault (with the potential of crashing the kernel +as a whole, if panic_on_oops is set)." + +The way to fix this is to realize that the we can only relay on the +registers that IRET restores. The two that are guaranteed are the +%cs and %ss as they are always fixed GDT selectors. Also they are +inaccessible from user mode - so they cannot be altered. This is +the approach taken in this patch. + +Another alternative option suggested by Jan would be to relay on +the subtle realization that using the %ebp or %esp relative references uses +the %ss segment. In which case we could switch from using %eax to %ebp and +would not need the %ss over-rides. That would also require one extra +instruction to compensate for the one place where the register is used +as scaled index. However Andrew pointed out that is too subtle and if +further work was to be done in this code-path it could escape folks attention +and lead to accidents. + +Reviewed-by: Petr Matousek +Reported-by: Petr Matousek +Reviewed-by: Andrew Cooper +Signed-off-by: Jan Beulich +Signed-off-by: Konrad Rzeszutek Wilk +--- + arch/x86/xen/xen-asm_32.S | 14 +++++++------- + 1 files changed, 7 insertions(+), 7 deletions(-) + +diff --git a/arch/x86/xen/xen-asm_32.S b/arch/x86/xen/xen-asm_32.S +index f9643fc..33ca6e4 100644 +--- a/arch/x86/xen/xen-asm_32.S ++++ b/arch/x86/xen/xen-asm_32.S +@@ -89,11 +89,11 @@ ENTRY(xen_iret) + */ + #ifdef CONFIG_SMP + GET_THREAD_INFO(%eax) +- movl TI_cpu(%eax), %eax +- movl __per_cpu_offset(,%eax,4), %eax +- mov xen_vcpu(%eax), %eax ++ movl %ss:TI_cpu(%eax), %eax ++ movl %ss:__per_cpu_offset(,%eax,4), %eax ++ mov %ss:xen_vcpu(%eax), %eax + #else +- movl xen_vcpu, %eax ++ movl %ss:xen_vcpu, %eax + #endif + + /* check IF state we're restoring */ +@@ -106,11 +106,11 @@ ENTRY(xen_iret) + * resuming the code, so we don't have to be worried about + * being preempted to another CPU. + */ +- setz XEN_vcpu_info_mask(%eax) ++ setz %ss:XEN_vcpu_info_mask(%eax) + xen_iret_start_crit: + + /* check for unmasked and pending */ +- cmpw $0x0001, XEN_vcpu_info_pending(%eax) ++ cmpw $0x0001, %ss:XEN_vcpu_info_pending(%eax) + + /* + * If there's something pending, mask events again so we can +@@ -118,7 +118,7 @@ xen_iret_start_crit: + * touch XEN_vcpu_info_mask. + */ + jne 1f +- movb $1, XEN_vcpu_info_mask(%eax) ++ movb $1, %ss:XEN_vcpu_info_mask(%eax) + + 1: popl %eax + +-- +1.7.7.6 +