Commit-ID: aa78c1ccfab6018289bc2bfd0092d516d0a49ec5
Gitweb: http://git.kernel.org/tip/aa78c1ccfab6018289bc2bfd0092d516d0a49ec5
Author: Borislav Petkov <bp@xxxxxxx>
AuthorDate: Fri, 25 Aug 2017 12:04:56 +0200
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Tue, 29 Aug 2017 10:59:28 +0200
x86/microcode/intel: Improve microcode patches saving flow
Avoid potentially dereferencing a NULL pointer when saving a microcode
patch for early loading on the application processors.
While at it, drop the IS_ERR() checking in favor of simpler, NULL-ptr
checks which are sufficient and rename __alloc_microcode_buf() to
memdup_patch() to more precisely denote what it does.
No functionality change.
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: kernel-janitors@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/20170825100456.n236w3jebteokfd6@xxxxxxx
---
arch/x86/kernel/cpu/microcode/intel.c | 27 ++++++++++++++-------------
1 file changed, 14 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 59edbe9..8f7a9bb 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -146,18 +146,18 @@ static bool microcode_matches(struct microcode_header_intel *mc_header,
return false;
}
-static struct ucode_patch *__alloc_microcode_buf(void *data, unsigned int size)
+static struct ucode_patch *memdup_patch(void *data, unsigned int size)
{
struct ucode_patch *p;
p = kzalloc(sizeof(struct ucode_patch), GFP_KERNEL);
if (!p)
- return ERR_PTR(-ENOMEM);
+ return NULL;
p->data = kmemdup(data, size, GFP_KERNEL);
if (!p->data) {
kfree(p);
- return ERR_PTR(-ENOMEM);
+ return NULL;
}
return p;
@@ -183,8 +183,8 @@ static void save_microcode_patch(void *data, unsigned int size)
if (mc_hdr->rev <= mc_saved_hdr->rev)
continue;
- p = __alloc_microcode_buf(data, size);
- if (IS_ERR(p))
+ p = memdup_patch(data, size);
+ if (!p)
pr_err("Error allocating buffer %p\n", data);
else
list_replace(&iter->plist, &p->plist);
@@ -196,24 +196,25 @@ static void save_microcode_patch(void *data, unsigned int size)
* newly found.
*/
if (!prev_found) {
- p = __alloc_microcode_buf(data, size);
- if (IS_ERR(p))
+ p = memdup_patch(data, size);
+ if (!p)
pr_err("Error allocating buffer for %p\n", data);
else
list_add_tail(&p->plist, µcode_cache);
}
+ if (!p)
+ return;
+
/*
* Save for early loading. On 32-bit, that needs to be a physical
* address as the APs are running from physical addresses, before
* paging has been enabled.
*/
- if (p) {
- if (IS_ENABLED(CONFIG_X86_32))
- intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
- else
- intel_ucode_patch = p->data;
- }
+ if (IS_ENABLED(CONFIG_X86_32))
+ intel_ucode_patch = (struct microcode_intel *)__pa_nodebug(p->data);
+ else
+ intel_ucode_patch = p->data;
}
static int microcode_sanity_check(void *mc, int print_err)
--
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