| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <Yytb67xvrnctxnEe@work>
Date: Wed, 21 Sep 2022 13:46:03 -0500
From: "Gustavo A. R. Silva" <gustavoars@...nel.org>
To: Dave Hansen <dave.hansen@...ux.intel.com>,
Andy Lutomirski <luto@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>
Cc: x86@...nel.org, linux-kernel@...r.kernel.org,
"Gustavo A. R. Silva" <gustavoars@...nel.org>,
linux-hardening@...r.kernel.org
Subject: [PATCH][next] mm/pgtable: Fix multiple -Wstringop-overflow warnings
The actual size of the following arrays at run-time depends on
CONFIG_X86_PAE.
427 pmd_t *u_pmds[MAX_PREALLOCATED_USER_PMDS];
428 pmd_t *pmds[MAX_PREALLOCATED_PMDS];
If CONFIG_X86_PAE is not enabled, their final size will be zero. In that
case, the compiler complains about trying to access objects of size zero
when calling functions where these objects are passed as arguments.
Fix this by sanity-checking the size of those arrays just before the
function calls. Also, the following warnings are fixed by these changes
when building with GCC-11 and -Wstringop-overflow enabled:
arch/x86/mm/pgtable.c:437:13: warning: ‘preallocate_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
arch/x86/mm/pgtable.c:440:13: warning: ‘preallocate_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
arch/x86/mm/pgtable.c:462:9: warning: ‘free_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
arch/x86/mm/pgtable.c:455:9: warning: ‘pgd_prepopulate_user_pmd’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
arch/x86/mm/pgtable.c:464:9: warning: ‘free_pmds.constprop’ accessing 8 bytes in a region of size 0 [-Wstringop-overflow=]
This helps with the ongoing efforts to globally enable
-Wstringop-overflow.
Link: https://github.com/KSPP/linux/issues/203
Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>
---
arch/x86/mm/pgtable.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 8525f2876fb4..5116df6a308c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -434,10 +434,12 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
mm->pgd = pgd;
- if (preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
+ if (sizeof(pmds) != 0 &&
+ preallocate_pmds(mm, pmds, PREALLOCATED_PMDS) != 0)
goto out_free_pgd;
- if (preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
+ if (sizeof(u_pmds) != 0 &&
+ preallocate_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS) != 0)
goto out_free_pmds;
if (paravirt_pgd_alloc(mm) != 0)
@@ -451,17 +453,22 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
spin_lock(&pgd_lock);
pgd_ctor(mm, pgd);
- pgd_prepopulate_pmd(mm, pgd, pmds);
- pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
+ if (sizeof(pmds) != 0)
+ pgd_prepopulate_pmd(mm, pgd, pmds);
+
+ if (sizeof(u_pmds) != 0)
+ pgd_prepopulate_user_pmd(mm, pgd, u_pmds);
spin_unlock(&pgd_lock);
return pgd;
out_free_user_pmds:
- free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
+ if (sizeof(u_pmds) != 0)
+ free_pmds(mm, u_pmds, PREALLOCATED_USER_PMDS);
out_free_pmds:
- free_pmds(mm, pmds, PREALLOCATED_PMDS);
+ if (sizeof(pmds) != 0)
+ free_pmds(mm, pmds, PREALLOCATED_PMDS);
out_free_pgd:
_pgd_free(pgd);
out:
--
2.34.1
Powered by blists - more mailing lists