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| author | Borislav Petkov <bp@suse.de> | 2018-01-23 11:41:33 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-31 14:03:49 +0100 |
| commit | cbfb351be483a239a2afaa4702826b0ad359fd1e (patch) | |
| tree | 5733cd93fe402f8878a521511323a99eabfc1a5a /arch | |
| parent | ac2cc887653808e988f9d7ece50aacc755a4f879 (diff) | |
| download | linux-stable-cbfb351be483a239a2afaa4702826b0ad359fd1e.tar.gz linux-stable-cbfb351be483a239a2afaa4702826b0ad359fd1e.tar.bz2 linux-stable-cbfb351be483a239a2afaa4702826b0ad359fd1e.zip | |
x86/microcode: Fix again accessing initrd after having been freed
commit 1d080f096fe33f031d26e19b3ef0146f66b8b0f1 upstream.
Commit 24c2503255d3 ("x86/microcode: Do not access the initrd after it has
been freed") fixed attempts to access initrd from the microcode loader
after it has been freed. However, a similar KASAN warning was reported
(stack trace edited):
smpboot: Booting Node 0 Processor 1 APIC 0x11
==================================================================
BUG: KASAN: use-after-free in find_cpio_data+0x9b5/0xa50
Read of size 1 at addr ffff880035ffd000 by task swapper/1/0
CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.14.8-slack #7
Hardware name: System manufacturer System Product Name/A88X-PLUS, BIOS 3003 03/10/2016
Call Trace:
dump_stack
print_address_description
kasan_report
? find_cpio_data
__asan_report_load1_noabort
find_cpio_data
find_microcode_in_initrd
__load_ucode_amd
load_ucode_amd_ap
load_ucode_ap
After some investigation, it turned out that a merge was done using the
wrong side to resolve, leading to picking up the previous state, before
the 24c2503255d3 fix. Therefore the Fixes tag below contains a merge
commit.
Revert the mismerge by catching the save_microcode_in_initrd_amd()
retval and thus letting the function exit with the last return statement
so that initrd_gone can be set to true.
Fixes: f26483eaedec ("Merge branch 'x86/urgent' into x86/microcode, to resolve conflicts")
Reported-by: <higuita@gmx.net>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=198295
Link: https://lkml.kernel.org/r/20180123104133.918-2-bp@alien8.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/cpu/microcode/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/cpu/microcode/core.c b/arch/x86/kernel/cpu/microcode/core.c index c4fa4a85d4cb..e4fc595cd6ea 100644 --- a/arch/x86/kernel/cpu/microcode/core.c +++ b/arch/x86/kernel/cpu/microcode/core.c @@ -239,7 +239,7 @@ static int __init save_microcode_in_initrd(void) break; case X86_VENDOR_AMD: if (c->x86 >= 0x10) - return save_microcode_in_initrd_amd(cpuid_eax(1)); + ret = save_microcode_in_initrd_amd(cpuid_eax(1)); break; default: break; |