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Commit7d53be5

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Merge tag 'x86_urgent_for_v5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov: - An IOMMU VT-d build fix when CONFIG_PCI_ATS=n along with a revert of same because the proper one is going through the IOMMU tree (Thomas Gleixner) - An Intel microcode loader fix to save the correct microcode patch to apply during resume (Chen Yu) - A fix to not access user memory of other processes when dumping opcode bytes (Thomas Gleixner)* tag 'x86_urgent_for_v5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: Revert "iommu/vt-d: Take CONFIG_PCI_ATS into account" x86/dumpstack: Do not try to access user space code of other tasks x86/microcode/intel: Check patch signature before saving microcode for early loading iommu/vt-d: Take CONFIG_PCI_ATS into account
2 parents4a51c60 +01cf158 commit7d53be5

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2 files changed

+29
-57
lines changed

2 files changed

+29
-57
lines changed

‎arch/x86/kernel/cpu/microcode/intel.c‎

Lines changed: 10 additions & 53 deletions
Original file line numberDiff line numberDiff line change
@@ -100,53 +100,6 @@ static int has_newer_microcode(void *mc, unsigned int csig, int cpf, int new_rev
100100
returnfind_matching_signature(mc,csig,cpf);
101101
}
102102

103-
/*
104-
* Given CPU signature and a microcode patch, this function finds if the
105-
* microcode patch has matching family and model with the CPU.
106-
*
107-
* %true - if there's a match
108-
* %false - otherwise
109-
*/
110-
staticboolmicrocode_matches(structmicrocode_header_intel*mc_header,
111-
unsigned longsig)
112-
{
113-
unsigned longtotal_size=get_totalsize(mc_header);
114-
unsigned longdata_size=get_datasize(mc_header);
115-
structextended_sigtable*ext_header;
116-
unsignedintfam_ucode,model_ucode;
117-
structextended_signature*ext_sig;
118-
unsignedintfam,model;
119-
intext_sigcount,i;
120-
121-
fam=x86_family(sig);
122-
model=x86_model(sig);
123-
124-
fam_ucode=x86_family(mc_header->sig);
125-
model_ucode=x86_model(mc_header->sig);
126-
127-
if (fam==fam_ucode&&model==model_ucode)
128-
return true;
129-
130-
/* Look for ext. headers: */
131-
if (total_size <=data_size+MC_HEADER_SIZE)
132-
return false;
133-
134-
ext_header= (void*)mc_header+data_size+MC_HEADER_SIZE;
135-
ext_sig= (void*)ext_header+EXT_HEADER_SIZE;
136-
ext_sigcount=ext_header->count;
137-
138-
for (i=0;i<ext_sigcount;i++) {
139-
fam_ucode=x86_family(ext_sig->sig);
140-
model_ucode=x86_model(ext_sig->sig);
141-
142-
if (fam==fam_ucode&&model==model_ucode)
143-
return true;
144-
145-
ext_sig++;
146-
}
147-
return false;
148-
}
149-
150103
staticstructucode_patch*memdup_patch(void*data,unsignedintsize)
151104
{
152105
structucode_patch*p;
@@ -164,7 +117,7 @@ static struct ucode_patch *memdup_patch(void *data, unsigned int size)
164117
returnp;
165118
}
166119

167-
staticvoidsave_microcode_patch(void*data,unsignedintsize)
120+
staticvoidsave_microcode_patch(structucode_cpu_info*uci,void*data,unsignedintsize)
168121
{
169122
structmicrocode_header_intel*mc_hdr,*mc_saved_hdr;
170123
structucode_patch*iter,*tmp,*p=NULL;
@@ -210,6 +163,9 @@ static void save_microcode_patch(void *data, unsigned int size)
210163
if (!p)
211164
return;
212165

166+
if (!find_matching_signature(p->data,uci->cpu_sig.sig,uci->cpu_sig.pf))
167+
return;
168+
213169
/*
214170
* Save for early loading. On 32-bit, that needs to be a physical
215171
* address as the APs are running from physical addresses, before
@@ -344,13 +300,14 @@ scan_microcode(void *data, size_t size, struct ucode_cpu_info *uci, bool save)
344300

345301
size-=mc_size;
346302

347-
if (!microcode_matches(mc_header,uci->cpu_sig.sig)) {
303+
if (!find_matching_signature(data,uci->cpu_sig.sig,
304+
uci->cpu_sig.pf)) {
348305
data+=mc_size;
349306
continue;
350307
}
351308

352309
if (save) {
353-
save_microcode_patch(data,mc_size);
310+
save_microcode_patch(uci,data,mc_size);
354311
gotonext;
355312
}
356313

@@ -483,14 +440,14 @@ static void show_saved_mc(void)
483440
* Save this microcode patch. It will be loaded early when a CPU is
484441
* hot-added or resumes.
485442
*/
486-
staticvoidsave_mc_for_early(u8*mc,unsignedintsize)
443+
staticvoidsave_mc_for_early(structucode_cpu_info*uci,u8*mc,unsignedintsize)
487444
{
488445
/* Synchronization during CPU hotplug. */
489446
staticDEFINE_MUTEX(x86_cpu_microcode_mutex);
490447

491448
mutex_lock(&x86_cpu_microcode_mutex);
492449

493-
save_microcode_patch(mc,size);
450+
save_microcode_patch(uci,mc,size);
494451
show_saved_mc();
495452

496453
mutex_unlock(&x86_cpu_microcode_mutex);
@@ -935,7 +892,7 @@ static enum ucode_state generic_load_microcode(int cpu, struct iov_iter *iter)
935892
* permanent memory. So it will be loaded early when a CPU is hot added
936893
* or resumes.
937894
*/
938-
save_mc_for_early(new_mc,new_mc_size);
895+
save_mc_for_early(uci,new_mc,new_mc_size);
939896

940897
pr_debug("CPU%d found a matching microcode update with version 0x%x (current=0x%x)\n",
941898
cpu,new_rev,uci->cpu_sig.rev);

‎arch/x86/kernel/dumpstack.c‎

Lines changed: 19 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -78,13 +78,22 @@ static int copy_code(struct pt_regs *regs, u8 *buf, unsigned long src,
7878
if (!user_mode(regs))
7979
returncopy_from_kernel_nofault(buf, (u8*)src,nbytes);
8080

81+
/* The user space code from other tasks cannot be accessed. */
82+
if (regs!=task_pt_regs(current))
83+
return-EPERM;
8184
/*
8285
* Make sure userspace isn't trying to trick us into dumping kernel
8386
* memory by pointing the userspace instruction pointer at it.
8487
*/
8588
if (__chk_range_not_ok(src,nbytes,TASK_SIZE_MAX))
8689
return-EINVAL;
8790

91+
/*
92+
* Even if named copy_from_user_nmi() this can be invoked from
93+
* other contexts and will not try to resolve a pagefault, which is
94+
* the correct thing to do here as this code can be called from any
95+
* context.
96+
*/
8897
returncopy_from_user_nmi(buf, (void__user*)src,nbytes);
8998
}
9099

@@ -115,13 +124,19 @@ void show_opcodes(struct pt_regs *regs, const char *loglvl)
115124
u8opcodes[OPCODE_BUFSIZE];
116125
unsigned longprologue=regs->ip-PROLOGUE_SIZE;
117126

118-
if (copy_code(regs,opcodes,prologue,sizeof(opcodes))) {
119-
printk("%sCode: Unable to access opcode bytes at RIP 0x%lx.\n",
120-
loglvl,prologue);
121-
}else {
127+
switch (copy_code(regs,opcodes,prologue,sizeof(opcodes))) {
128+
case0:
122129
printk("%sCode: %"__stringify(PROLOGUE_SIZE)"ph <%02x> %"
123130
__stringify(EPILOGUE_SIZE)"ph\n",loglvl,opcodes,
124131
opcodes[PROLOGUE_SIZE],opcodes+PROLOGUE_SIZE+1);
132+
break;
133+
case-EPERM:
134+
/* No access to the user space stack of other tasks. Ignore. */
135+
break;
136+
default:
137+
printk("%sCode: Unable to access opcode bytes at RIP 0x%lx.\n",
138+
loglvl,prologue);
139+
break;
125140
}
126141
}
127142

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