Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1358394

[PATCH 4.2.y-ckt 56/98] parisc: Fix ptrace syscall number and return value modification

From Kamal Mostafa <kamal@canonical.com>
Newsgroups linux.kernel
Subject [PATCH 4.2.y-ckt 56/98] parisc: Fix ptrace syscall number and return value modification
Date 2016-03-16 00:50 +0100
Message-ID <rd6ST-Ip-39@gated-at.bofh.it> (permalink)
References <rd6Jb-EH-5@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw

4.2.8-ckt6 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Helge Deller <deller@gmx.de>

commit 98e8b6c9ac9d1b1e9d1122dfa6783d5d566bb8f7 upstream.

Mike Frysinger reported that his ptrace testcase showed strange
behaviour on parisc: It was not possible to avoid a syscall and the
return value of a syscall couldn't be changed.

To modify a syscall number, we were missing to save the new syscall
number to gr20 which is then picked up later in assembly again.

The effect that the return value couldn't be changed is a side-effect of
another bug in the assembly code. When a process is ptraced, userspace
expects each syscall to report entrance and exit of a syscall.  If a
syscall number was given which doesn't exist, we jumped to the normal
syscall exit code instead of informing userspace that the (non-existant)
syscall exits. This unexpected behaviour confuses userspace and thus the
bug was misinterpreted as if we can't change the return value.

This patch fixes both problems and was tested on 64bit kernel with
32bit userspace.

Signed-off-by: Helge Deller <deller@gmx.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Tested-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
 arch/parisc/kernel/ptrace.c  | 16 +++++++++++-----
 arch/parisc/kernel/syscall.S |  5 ++++-
 2 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/arch/parisc/kernel/ptrace.c b/arch/parisc/kernel/ptrace.c
index 9585c81..ce0b2b4 100644
--- a/arch/parisc/kernel/ptrace.c
+++ b/arch/parisc/kernel/ptrace.c
@@ -269,14 +269,19 @@ long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
 
 long do_syscall_trace_enter(struct pt_regs *regs)
 {
-	long ret = 0;
-
 	/* Do the secure computing check first. */
 	secure_computing_strict(regs->gr[20]);
 
 	if (test_thread_flag(TIF_SYSCALL_TRACE) &&
-	    tracehook_report_syscall_entry(regs))
-		ret = -1L;
+	    tracehook_report_syscall_entry(regs)) {
+		/*
+		 * Tracing decided this syscall should not happen or the
+		 * debugger stored an invalid system call number. Skip
+		 * the system call and the system call restart handling.
+		 */
+		regs->gr[20] = -1UL;
+		goto out;
+	}
 
 #ifdef CONFIG_64BIT
 	if (!is_compat_task())
@@ -290,7 +295,8 @@ long do_syscall_trace_enter(struct pt_regs *regs)
 			regs->gr[24] & 0xffffffff,
 			regs->gr[23] & 0xffffffff);
 
-	return ret ? : regs->gr[20];
+out:
+	return regs->gr[20];
 }
 
 void do_syscall_trace_exit(struct pt_regs *regs)
diff --git a/arch/parisc/kernel/syscall.S b/arch/parisc/kernel/syscall.S
index 0b8d26d..02cf40c 100644
--- a/arch/parisc/kernel/syscall.S
+++ b/arch/parisc/kernel/syscall.S
@@ -343,7 +343,7 @@ tracesys_next:
 #endif
 
 	comiclr,>>=	__NR_Linux_syscalls, %r20, %r0
-	b,n	.Lsyscall_nosys
+	b,n	.Ltracesys_nosys
 
 	LDREGX  %r20(%r19), %r19
 
@@ -359,6 +359,9 @@ tracesys_next:
 	be      0(%sr7,%r19)
 	ldo	R%tracesys_exit(%r2),%r2
 
+.Ltracesys_nosys:
+	ldo	-ENOSYS(%r0),%r28		/* set errno */
+
 	/* Do *not* call this function on the gateway page, because it
 	makes a direct call to syscall_trace. */
 	
-- 
2.7.0

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[4.2.y-ckt stable] Linux 4.2.8-ckt6 stable review Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 21/98] iommu/amd: Fix boot warning when device 00:00.0 is not iommu covered Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 87/98] tcp: fix tcpi_segs_in after connection establishment Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 65/98] ovl: fix getcwd() failure after unsuccessful rmdir Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 89/98] tcp: convert cached rtt from usec to jiffies when feeding initial rto Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 08/98] mac80211: minstrel: Change expected throughput unit back to Kbps Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 88/98] be2net: Don't leak iomapped memory on removal. Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 83/98] MIPS: Fix build error when SMP is used without GIC Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 93/98] ipv6: re-enable fragment header matching in ipv6_find_hdr Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 82/98] dmaengine: at_xdmac: fix residue computation Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 60/98] drm/radeon/pm: update current crtc info after setting the powerstate Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 85/98] dmaengine: pxa_dma: fix cyclic transfers Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 37/98] arm/arm64: KVM: Fix ioctl error handling Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 94/98] net/mlx5e: Remove wrong poll CQ optimization Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 77/98] jffs2: reduce the breakage on recovery from halfway failed rename() Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 86/98] MIPS: smp.c: Fix uninitialised temp_foreign_map Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 98/98] mld, igmp: Fix reserved tailroom calculation Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:40 +0100
  [PATCH 4.2.y-ckt 63/98] ALSA: hda - Fix mic issues on Acer Aspire E1-472 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 76/98] ncpfs: fix a braino in OOM handling in ncp_fill_cache() Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 70/98] target: Drop incorrect ABORT_TASK put for completed commands Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 58/98] USB: qcserial: add Sierra Wireless EM74xx device ID Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 50/98] USB: serial: option: add support for Quectel UC20 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 79/98] arm64: account for sparsemem section alignment when choosing vmemmap offset Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 61/98] drm/amdgpu: return from atombios_dp_get_dpcd only when error Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 80/98] tracing: Fix check for cpu online when event is disabled Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 47/98] ASoC: wm8994: Fix enum ctl accesses in a wrong type Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 44/98] USB: cp210x: Add ID for Parrot NMEA GPS Flight Recorder Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 45/98] ASoC: dapm: Fix ctl value accesses in a wrong type Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 57/98] drm/ast: Fix incorrect register check for DRAM width Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 46/98] ASoC: wm8958: Fix enum ctl accesses in a wrong type Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 49/98] USB: serial: option: add support for Telit LE922 PID 0x1045 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 59/98] drm/amdgpu/pm: update current crtc info after setting the powerstate Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 48/98] ASoC: wm_adsp: Fix enum ctl accesses in a wrong type Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 42/98] use ->d_seq to get coherency between ->d_inode and ->d_flags Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 54/98] i2c: brcmstb: allocate correct amount of memory for regmap Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 56/98] parisc: Fix ptrace syscall number and return value modification Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 66/98] ovl: ignore lower entries when checking purity of non-directory entries Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 51/98] ALSA: usb-audio: Add a quirk for Plantronics DA45 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 72/98] ARM: dts: dra7: do not gate cpsw clock due to errata i877 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 43/98] USB: qcserial: add Dell Wireless 5809e Gobi 4G HSPA+ (rev3) Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 78/98] KVM: VMX: disable PEBS before a guest entry Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 68/98] MIPS: traps: Fix SIGFPE information leak from `do_ov' and `do_trap_or_bp' Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 71/98] ARM: OMAP2+: hwmod: Introduce ti,no-idle dt property Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 62/98] PM / sleep / x86: Fix crash on graph trace through x86 suspend Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 55/98] ALSA: seq: oss: Don't drain at closing a client Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 73/98] PCI: Allow a NULL "parent" pointer in pci_bus_assign_domain_nr() Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 41/98] ALSA: hdsp: Fix wrong boolean ctl value accesses Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 52/98] mac80211: check PN correctly for GCMP-encrypted fragmented MPDUs Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 81/98] KVM: MMU: fix ept=0/pte.u=1/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo Kamal Mostafa <kamal@canonical.com> - 2016-03-16 00:50 +0100
  [PATCH 4.2.y-ckt 29/98] ALSA: ctl: Fix ioctls for X32 ABI Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 26/98] KVM: x86: fix root cause for missed hardware breakpoints Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 10/98] iwlwifi: mvm: inc pending frames counter also when txing non-sta Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 35/98] CIFS: Fix SMB2+ interim response processing for read requests Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 16/98] mac80211: minstrel_ht: set default tx aggregation timeout to 0 Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 02/98] tipc: fix nullptr crash during subscription cancel Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 09/98] libata: fix HDIO_GET_32BIT ioctl Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 39/98] ALSA: hdspm: Fix wrong boolean ctl value accesses Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 18/98] Revert "jffs2: Fix lock acquisition order bug in jffs2_write_begin" Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 27/98] arm64: vmemmap: use virtual projection of linear region Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 06/98] cfg80211/wext: fix message ordering Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 34/98] cifs: fix out-of-bounds access in lease parsing Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 40/98] ALSA: hdspm: Fix zero-division Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 22/98] iommu/amd: Apply workaround for ATS write permission check Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 13/98] ahci: Order SATA device IDs for codename Lewisburg Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 04/98] Input: aiptek - fix crash on detecting device without endpoints Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 01/98] tipc: fix connection abort during subscription cancel Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 31/98] ALSA: rawmidi: Fix ioctls X32 ABI Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 14/98] Adding Intel Lewisburg device IDs for SATA Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 05/98] wext: fix message delay/ordering Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 07/98] mac80211: fix use of uninitialised values in RX aggregation Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 11/98] [media] adv7604: fix tx 5v detect regression Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 20/98] Fix directory hardlinks from deleted directories Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 25/98] fbcon: set a default value to blink interval Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 23/98] libata: Align ata_device's id on a cacheline Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 30/98] ALSA: pcm: Fix ioctls for X32 ABI Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 33/98] ALSA: timer: Fix ioctls for X32 ABI Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 38/98] MIPS: kvm: Fix ioctl error handling. Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 28/98] vfio: fix ioctl error handling Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 17/98] usb: chipidea: otg: change workqueue ci_otg as freezable Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 36/98] Fix cifs_uniqueid_to_ino_t() function for s390x Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100
  [PATCH 4.2.y-ckt 24/98] can: gs_usb: fixed disconnect bug by removing erroneous use of kfree() Kamal Mostafa <kamal@canonical.com> - 2016-03-16 01:00 +0100

csiph-web