* [PATCHv2 00/19] arm64: invoke syscalls with pt_regs @ 2018-06-01 11:24 Mark Rutland 2018-06-01 11:24 ` [PATCHv2 14/19] kernel: add kcompat_sys_{f,}statfs64() Mark Rutland 0 siblings, 1 reply; 2+ messages in thread From: Mark Rutland @ 2018-06-01 11:24 UTC (permalink / raw) To: linux-arm-kernel, linux-kernel, will.deacon, catalin.marinas Cc: Mark Rutland, dave.martin, hch, james.morse, linux-fsdevel, linux, marc.zyngier, viro This series reworks arm64's syscall handling to minimize the propagation of user-controlled register values into speculated code paths. As with x86 [1], a wrapper is generated for each syscall, which extracts the argument from a struct pt_regs. During kernel entry from userspace, registers are zeroed. The arm64 kernel code directly invokes some syscalls which the x86 code doesn't, so I've added ksys_* wrappers for these, following the x86 example. The rest of the series is arm64-specific. I've pushed the series out to my arm64/syscall-regs branch [2] on kernel.org. Since v1 [3]: * Rebase atop of arm64 for-next/core (for SSBD conflicts) * Move ksys_personality logic into <linux/syscalls.h> * Move kcompat_sys_* wrappers to <linux/compat.h> * Fix scno bounds check to use unisgned comparison * Fix sve_user_reset() call in el0_svc_handler() * Add BUILD_BUG() to the !CONFIG_ARM64_SVE stubs * Accumulate acked-by / reviewed-by tags Thanks, Mark. [1] https://lkml.kernel.org/r/20180330093720.6780-1-linux@dominikbrodowski.net [2] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git [3] https://lkml.kernel.org/r/20180514094640.27569-1-mark.rutland@arm.com Mark Rutland (19): arm64: consistently use unsigned long for thread flags arm64: move SCTLR_EL{1,2} assertions to <asm/sysreg.h> arm64: introduce sysreg_clear_set() arm64: kill config_sctlr_el1() arm64: kill change_cpacr() arm64: move sve_user_{enable,disable} to <asm/fpsimd.h> arm64: remove sigreturn wrappers arm64: convert raw syscall invocation to C arm64: convert syscall trace logic to C arm64: convert native/compat syscall entry to C arm64: don't reload GPRs after apply_ssbd arm64: zero GPRs upon entry from EL0 kernel: add ksys_personality() kernel: add kcompat_sys_{f,}statfs64() arm64: remove in-kernel call to sys_personality() arm64: use {COMPAT,}SYSCALL_DEFINE0 for sigreturn arm64: use SYSCALL_DEFINE6() for mmap arm64: convert compat wrappers to C arm64: implement syscall wrappers arch/arm64/Kconfig | 1 + arch/arm64/include/asm/fpsimd.h | 17 +++- arch/arm64/include/asm/syscall_wrapper.h | 80 +++++++++++++++++ arch/arm64/include/asm/sysreg.h | 33 ++++--- arch/arm64/include/asm/unistd32.h | 26 +++--- arch/arm64/kernel/Makefile | 5 +- arch/arm64/kernel/armv8_deprecated.c | 8 +- arch/arm64/kernel/cpu_errata.c | 3 +- arch/arm64/kernel/entry.S | 145 ++++--------------------------- arch/arm64/kernel/entry32.S | 121 -------------------------- arch/arm64/kernel/fpsimd.c | 19 ---- arch/arm64/kernel/signal.c | 5 +- arch/arm64/kernel/signal32.c | 6 +- arch/arm64/kernel/sys.c | 19 ++-- arch/arm64/kernel/sys32.c | 127 ++++++++++++++++++++++++--- arch/arm64/kernel/syscall.c | 114 ++++++++++++++++++++++++ arch/arm64/kernel/traps.c | 4 +- arch/arm64/mm/fault.c | 2 +- fs/statfs.c | 14 ++- include/linux/compat.h | 11 +++ include/linux/syscalls.h | 11 +++ 21 files changed, 437 insertions(+), 334 deletions(-) create mode 100644 arch/arm64/include/asm/syscall_wrapper.h delete mode 100644 arch/arm64/kernel/entry32.S create mode 100644 arch/arm64/kernel/syscall.c -- 2.11.0 ^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCHv2 14/19] kernel: add kcompat_sys_{f,}statfs64() 2018-06-01 11:24 [PATCHv2 00/19] arm64: invoke syscalls with pt_regs Mark Rutland @ 2018-06-01 11:24 ` Mark Rutland 0 siblings, 0 replies; 2+ messages in thread From: Mark Rutland @ 2018-06-01 11:24 UTC (permalink / raw) To: linux-arm-kernel, linux-kernel, will.deacon, catalin.marinas Cc: Mark Rutland, Al Viro, linux-fsdevel Using this helper allows us to avoid the in-kernel calls to the compat_sys_{f,}statfs64() sycalls, as are necessary for parameter mangling in arm64's compat handling. Following the example of ksys_* functions, kcompat_sys_* functions are intended to be a drop-in replacement for their compat_sys_* counterparts, with the same calling convention. This is necessary to enable conversion of arm64's syscall handling to use pt_regs wrappers. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org --- fs/statfs.c | 14 ++++++++++++-- include/linux/compat.h | 11 +++++++++++ 2 files changed, 23 insertions(+), 2 deletions(-) diff --git a/fs/statfs.c b/fs/statfs.c index 5b2a24f0f263..f0216629621d 100644 --- a/fs/statfs.c +++ b/fs/statfs.c @@ -335,7 +335,7 @@ static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstat return 0; } -COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) +int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, struct compat_statfs64 __user * buf) { struct kstatfs tmp; int error; @@ -349,7 +349,12 @@ COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, s return error; } -COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) +COMPAT_SYSCALL_DEFINE3(statfs64, const char __user *, pathname, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_statfs64(pathname, sz, buf); +} + +int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, struct compat_statfs64 __user * buf) { struct kstatfs tmp; int error; @@ -363,6 +368,11 @@ COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct co return error; } +COMPAT_SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, compat_size_t, sz, struct compat_statfs64 __user *, buf) +{ + return kcompat_sys_fstatfs64(fd, sz, buf); +} + /* * This is a copy of sys_ustat, just dealing with a structure layout. * Given how simple this syscall is that apporach is more maintainable diff --git a/include/linux/compat.h b/include/linux/compat.h index 081281ad5772..6cecf9f11d6b 100644 --- a/include/linux/compat.h +++ b/include/linux/compat.h @@ -1013,6 +1013,17 @@ static inline struct compat_timeval ns_to_compat_timeval(s64 nsec) return ctv; } +/* + * Kernel code should not call compat syscalls (i.e., compat_sys_xyzyyz()) + * directly. Instead, use one of the functions which work equivalently, such + * as the kcompat_sys_xyzyyz() functions prototyped below. + */ + +int kcompat_sys_statfs64(const char __user * pathname, compat_size_t sz, + struct compat_statfs64 __user * buf); +int kcompat_sys_fstatfs64(unsigned int fd, compat_size_t sz, + struct compat_statfs64 __user * buf); + #else /* !CONFIG_COMPAT */ #define is_compat_task() (0) -- 2.11.0 ^ permalink raw reply related [flat|nested] 2+ messages in thread
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