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authorBorislav Petkov <bp@suse.de>2020-02-04 13:28:41 +0100
committerBorislav Petkov <bp@suse.de>2020-02-13 18:58:39 +0100
commit6e5cf31fbe651bed7ba1df768f2e123531132417 (patch)
tree71adfc2e4f338edc3cfbf90a0b724a387d72d8fa /arch/x86
parentbb6d3fb354c5ee8d6bde2d576eb7220ea09862b9 (diff)
x86/mce/amd: Publish the bank pointer only after setup has succeeded
threshold_create_bank() creates a bank descriptor per MCA error thresholding counter which can be controlled over sysfs. It publishes the pointer to that bank in a per-CPU variable and then goes on to create additional thresholding blocks if the bank has such. However, that creation of additional blocks in allocate_threshold_blocks() can fail, leading to a use-after-free through the per-CPU pointer. Therefore, publish that pointer only after all blocks have been setup successfully. Fixes: 019f34fccfd5 ("x86, MCE, AMD: Move shared bank to node descriptor") Reported-by: Saar Amar <Saar.Amar@microsoft.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200128140846.phctkvx5btiexvbx@kili.mountain
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/cpu/mce/amd.c33
1 files changed, 16 insertions, 17 deletions
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
index b3a50d962851..e7313e5c497c 100644
--- a/arch/x86/kernel/cpu/mce/amd.c
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -1198,8 +1198,9 @@ static const char *get_name(unsigned int bank, struct threshold_block *b)
return buf_mcatype;
}
-static int allocate_threshold_blocks(unsigned int cpu, unsigned int bank,
- unsigned int block, u32 address)
+static int allocate_threshold_blocks(unsigned int cpu, struct threshold_bank *tb,
+ unsigned int bank, unsigned int block,
+ u32 address)
{
struct threshold_block *b = NULL;
u32 low, high;
@@ -1243,16 +1244,12 @@ static int allocate_threshold_blocks(unsigned int cpu, unsigned int bank,
INIT_LIST_HEAD(&b->miscj);
- if (per_cpu(threshold_banks, cpu)[bank]->blocks) {
- list_add(&b->miscj,
- &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj);
- } else {
- per_cpu(threshold_banks, cpu)[bank]->blocks = b;
- }
+ if (tb->blocks)
+ list_add(&b->miscj, &tb->blocks->miscj);
+ else
+ tb->blocks = b;
- err = kobject_init_and_add(&b->kobj, &threshold_ktype,
- per_cpu(threshold_banks, cpu)[bank]->kobj,
- get_name(bank, b));
+ err = kobject_init_and_add(&b->kobj, &threshold_ktype, tb->kobj, get_name(bank, b));
if (err)
goto out_free;
recurse:
@@ -1260,7 +1257,7 @@ recurse:
if (!address)
return 0;
- err = allocate_threshold_blocks(cpu, bank, block, address);
+ err = allocate_threshold_blocks(cpu, tb, bank, block, address);
if (err)
goto out_free;
@@ -1345,8 +1342,6 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank)
goto out_free;
}
- per_cpu(threshold_banks, cpu)[bank] = b;
-
if (is_shared_bank(bank)) {
refcount_set(&b->cpus, 1);
@@ -1357,9 +1352,13 @@ static int threshold_create_bank(unsigned int cpu, unsigned int bank)
}
}
- err = allocate_threshold_blocks(cpu, bank, 0, msr_ops.misc(bank));
- if (!err)
- goto out;
+ err = allocate_threshold_blocks(cpu, b, bank, 0, msr_ops.misc(bank));
+ if (err)
+ goto out_free;
+
+ per_cpu(threshold_banks, cpu)[bank] = b;
+
+ return 0;
out_free:
kfree(b);