From d83c12656c952409fe54c8aded3ea50da59b17e8 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 12 Mar 2021 11:03:15 +0100 Subject: [PATCH] 5.4-stable patches added patches: powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch --- ...-of-user-pages-mapped-with-prot_none.patch | 96 +++++++++++++++++++ queue-5.4/series | 1 + 2 files changed, 97 insertions(+) create mode 100644 queue-5.4/powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch diff --git a/queue-5.4/powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch b/queue-5.4/powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch new file mode 100644 index 00000000000..800f30ace39 --- /dev/null +++ b/queue-5.4/powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch @@ -0,0 +1,96 @@ +From c119565a15a628efdfa51352f9f6c5186e506a1c Mon Sep 17 00:00:00 2001 +From: Christophe Leroy +Date: Mon, 1 Feb 2021 06:29:50 +0000 +Subject: powerpc/603: Fix protection of user pages mapped with PROT_NONE + +From: Christophe Leroy + +commit c119565a15a628efdfa51352f9f6c5186e506a1c upstream. + +On book3s/32, page protection is defined by the PP bits in the PTE +which provide the following protection depending on the access +keys defined in the matching segment register: +- PP 00 means RW with key 0 and N/A with key 1. +- PP 01 means RW with key 0 and RO with key 1. +- PP 10 means RW with both key 0 and key 1. +- PP 11 means RO with both key 0 and key 1. + +Since the implementation of kernel userspace access protection, +PP bits have been set as follows: +- PP00 for pages without _PAGE_USER +- PP01 for pages with _PAGE_USER and _PAGE_RW +- PP11 for pages with _PAGE_USER and without _PAGE_RW + +For kernelspace segments, kernel accesses are performed with key 0 +and user accesses are performed with key 1. As PP00 is used for +non _PAGE_USER pages, user can't access kernel pages not flagged +_PAGE_USER while kernel can. + +For userspace segments, both kernel and user accesses are performed +with key 0, therefore pages not flagged _PAGE_USER are still +accessible to the user. + +This shouldn't be an issue, because userspace is expected to be +accessible to the user. But unlike most other architectures, powerpc +implements PROT_NONE protection by removing _PAGE_USER flag instead of +flagging the page as not valid. This means that pages in userspace +that are not flagged _PAGE_USER shall remain inaccessible. + +To get the expected behaviour, just mimic other architectures in the +TLB miss handler by checking _PAGE_USER permission on userspace +accesses as if it was the _PAGE_PRESENT bit. + +Note that this problem only is only for 603 cores. The 604+ have +an hash table, and hash_page() function already implement the +verification of _PAGE_USER permission on userspace pages. + +Fixes: f342adca3afc ("powerpc/32s: Prepare Kernel Userspace Access Protection") +Cc: stable@vger.kernel.org # v5.2+ +Reported-by: Christoph Plattner +Signed-off-by: Christophe Leroy +Signed-off-by: Michael Ellerman +Link: https://lore.kernel.org/r/4a0c6e3bb8f0c162457bf54d9bc6fd8d7b55129f.1612160907.git.christophe.leroy@csgroup.eu +Signed-off-by: Greg Kroah-Hartman +--- + arch/powerpc/kernel/head_32.S | 9 ++++++--- + 1 file changed, 6 insertions(+), 3 deletions(-) + +--- a/arch/powerpc/kernel/head_32.S ++++ b/arch/powerpc/kernel/head_32.S +@@ -418,10 +418,11 @@ InstructionTLBMiss: + cmplw 0,r1,r3 + #endif + mfspr r2, SPRN_SPRG_PGDIR +- li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC ++ li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC | _PAGE_USER + #if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) + bge- 112f + lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */ ++ li r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC + addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */ + #endif + 112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */ +@@ -480,9 +481,10 @@ DataLoadTLBMiss: + lis r1,PAGE_OFFSET@h /* check if kernel address */ + cmplw 0,r1,r3 + mfspr r2, SPRN_SPRG_PGDIR +- li r1, _PAGE_PRESENT | _PAGE_ACCESSED ++ li r1, _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER + bge- 112f + lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */ ++ li r1, _PAGE_PRESENT | _PAGE_ACCESSED + addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */ + 112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */ + lwz r2,0(r2) /* get pmd entry */ +@@ -556,9 +558,10 @@ DataStoreTLBMiss: + lis r1,PAGE_OFFSET@h /* check if kernel address */ + cmplw 0,r1,r3 + mfspr r2, SPRN_SPRG_PGDIR +- li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED ++ li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_USER + bge- 112f + lis r2, (swapper_pg_dir - PAGE_OFFSET)@ha /* if kernel address, use */ ++ li r1, _PAGE_RW | _PAGE_DIRTY | _PAGE_PRESENT | _PAGE_ACCESSED + addi r2, r2, (swapper_pg_dir - PAGE_OFFSET)@l /* kernel page table */ + 112: rlwimi r2,r3,12,20,29 /* insert top 10 bits of address */ + lwz r2,0(r2) /* get pmd entry */ diff --git a/queue-5.4/series b/queue-5.4/series index 6684ef28aa0..091499e66e0 100644 --- a/queue-5.4/series +++ b/queue-5.4/series @@ -20,3 +20,4 @@ selftests-bpf-mask-bpf_csum_diff-return-value-to-16-bits-in-test_verifier.patch samples-bpf-add-missing-munmap-in-xdpsock.patch ibmvnic-always-store-valid-mac-address.patch mt76-dma-do-not-report-truncated-frames-to-mac80211.patch +powerpc-603-fix-protection-of-user-pages-mapped-with-prot_none.patch -- 2.47.2