Linux v5.6-rc2-47-g4b205766d8fc

0001-mm-Avoid-creating-virtual-address-aliases-in-brk-mma.patch

@@ -0,0 +1,95 @@
+From a34309d16f41c48ffd90e56a6f865d6a1a8c49f0 Mon Sep 17 00:00:00 2001
+From: Catalin Marinas <catalin.marinas@arm.com>
+Date: Wed, 19 Feb 2020 12:31:56 +0000
+Subject: [PATCH] mm: Avoid creating virtual address aliases in
+ brk()/mmap()/mremap()
+
+Currently the arm64 kernel ignores the top address byte passed to brk(),
+mmap() and mremap(). When the user is not aware of the 56-bit address
+limit or relies on the kernel to return an error, untagging such
+pointers has the potential to create address aliases in user-space.
+Passing a tagged address to munmap(), madvise() is permitted since the
+tagged pointer is expected to be inside an existing mapping.
+
+The current behaviour breaks the existing glibc malloc() implementation
+which relies on brk() with an address beyond 56-bit to be rejected by
+the kernel.
+
+Remove untagging in the above functions by partially reverting commit
+ce18d171cb73 ("mm: untag user pointers in mmap/munmap/mremap/brk"). In
+addition, update the arm64 tagged-address-abi.rst document accordingly.
+
+Link: https://bugzilla.redhat.com/1797052
+Fixes: ce18d171cb73 ("mm: untag user pointers in mmap/munmap/mremap/brk")
+Cc: <stable@vger.kernel.org> # 5.4.x-
+Cc: Andrew Morton <akpm@linux-foundation.org>
+Cc: Florian Weimer <fweimer@redhat.com>
+Reported-by: Victor Stinner <vstinner@redhat.com>
+Acked-by: Will Deacon <will@kernel.org>
+Acked-by: Andrey Konovalov <andreyknvl@google.com>
+Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
+---
+ Documentation/arm64/tagged-address-abi.rst | 11 +++++++++--
+ mm/mmap.c                                  |  4 ----
+ mm/mremap.c                                |  1 -
+ 3 files changed, 9 insertions(+), 7 deletions(-)
+
+diff --git a/Documentation/arm64/tagged-address-abi.rst b/Documentation/arm64/tagged-address-abi.rst
+index d4a85d535bf9..f6289116893c 100644
+--- a/Documentation/arm64/tagged-address-abi.rst
++++ b/Documentation/arm64/tagged-address-abi.rst
+@@ -44,8 +44,15 @@ The AArch64 Tagged Address ABI has two stages of relaxation depending
+ how the user addresses are used by the kernel:
+ 
+ 1. User addresses not accessed by the kernel but used for address space
+-   management (e.g. ``mmap()``, ``mprotect()``, ``madvise()``). The use
+-   of valid tagged pointers in this context is always allowed.
++   management (e.g. ``mprotect()``, ``madvise()``). The use of valid
++   tagged pointers in this context is allowed with the exception of
++   ``brk()``, ``mmap()`` and the ``new_address`` argument to
++   ``mremap()`` as these have the potential of aliasing with existing
++   user addresses.
++
++   NOTE: This behaviour changed in v5.6 and so some earlier kernels may
++   incorrectly accept valid tagged pointers for the ``brk()``,
++   ``mmap()`` and ``mremap()`` system calls.
+ 
+ 2. User addresses accessed by the kernel (e.g. ``write()``). This ABI
+    relaxation is disabled by default and the application thread needs to
+diff --git a/mm/mmap.c b/mm/mmap.c
+index 4390dbea4aa5..514cc19c5916 100644
+--- a/mm/mmap.c
++++ b/mm/mmap.c
+@@ -195,8 +195,6 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
+ 	bool downgraded = false;
+ 	LIST_HEAD(uf);
+ 
+-	brk = untagged_addr(brk);
+-
+ 	if (down_write_killable(&mm->mmap_sem))
+ 		return -EINTR;
+ 
+@@ -1583,8 +1581,6 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
+ 	struct file *file = NULL;
+ 	unsigned long retval;
+ 
+-	addr = untagged_addr(addr);
+-
+ 	if (!(flags & MAP_ANONYMOUS)) {
+ 		audit_mmap_fd(fd, flags);
+ 		file = fget(fd);
+diff --git a/mm/mremap.c b/mm/mremap.c
+index 1fc8a29fbe3f..1d98281f7204 100644
+--- a/mm/mremap.c
++++ b/mm/mremap.c
+@@ -607,7 +607,6 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
+ 	LIST_HEAD(uf_unmap);
+ 
+ 	addr = untagged_addr(addr);
+-	new_addr = untagged_addr(new_addr);
+ 
+ 	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
+ 		return ret;
+-- 
+2.24.1
+

gitrev

@@ -1 +1 @@
-b1da3acc781ce445445d959b41064d209a27bc2d
+4b205766d8fcb1627429ff31a4b36248b71a0df1

kernel.spec

@@ -107,7 +107,7 @@ Summary: The Linux kernel
 # The rc snapshot level
 %global rcrev 2
 # The git snapshot level
-%define gitrev 1
+%define gitrev 2
 # Set rpm version accordingly
 %define rpmversion 5.%{upstream_sublevel}.0
 %endif
@@ -865,6 +865,8 @@ Patch529: 0001-Include-kvm_asm.h-and-kvm_arm.h-in-kvm-arm-trace.h.patch
 
 Patch530: 0001-Replace-.ioctl-with-.compat_ioctl-in-three-appropria.patch
 
+Patch531: 0001-mm-Avoid-creating-virtual-address-aliases-in-brk-mma.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -2894,6 +2896,9 @@ fi
 #
 #
 %changelog
+* Wed Feb 19 2020 Jeremy Cline <jcline@redhat.com> - 5.6.0-0.rc2.git2.1
+- Linux v5.6-rc2-47-g4b205766d8fc
+
 * Tue Feb 18 2020 Jeremy Cline <jcline@redhat.com> - 5.6.0-0.rc2.git1.1
 - Linux v5.6-rc2-8-gb1da3acc781c
 - Enable CONFIG_INET_ESPINTCP (rhbz 1804255)

sources

@@ -1,3 +1,3 @@
 SHA512 (linux-5.5.tar.xz) = fa74fdabb5e63384a39e54da05b86a9ae9ea16179524b041fbbdffc7177e80b53600ae98d76be127ba216148f9dc55fe07ab20637e22c6d6030cb4aa09eb2f86
 SHA512 (patch-5.6-rc2.xz) = b49dfa43e7dcdf90bd68e582eb676f3cac53f7212d8abde6e41e18f8bd0eecc3ae2384639f8aaef8925c8e4385e75b0b49ec54e5bcfc23dec5fe2169cbce1af2
-SHA512 (patch-5.6-rc2-git1.xz) = ead71bb0efb09750beee0d3880571673f5d9063909aec055f8ab9158142ea2764d7faf421290090bdc2f7304375d08cd98d930be7db6ebff12569d0ec73495d4
+SHA512 (patch-5.6-rc2-git2.xz) = 023befa3b800d346736b5537c8d94b7856b594ee9f60150cb9989ed5d78b24defb4891e3bfb6fcbd7c13ecbadad7120d9626c07f9b9edeba8584f4e9bbf2372f