- 25 4月, 2018 1 次提交
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由 Eric W. Biederman 提交于
Call clear_siginfo to ensure every stack allocated siginfo is properly initialized before being passed to the signal sending functions. Note: It is not safe to depend on C initializers to initialize struct siginfo on the stack because C is allowed to skip holes when initializing a structure. The initialization of struct siginfo in tracehook_report_syscall_exit was moved from the helper user_single_step_siginfo into tracehook_report_syscall_exit itself, to make it clear that the local variable siginfo gets fully initialized. In a few cases the scope of struct siginfo has been reduced to make it clear that siginfo siginfo is not used on other paths in the function in which it is declared. Instances of using memset to initialize siginfo have been replaced with calls clear_siginfo for clarity. Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
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- 24 11月, 2017 1 次提交
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由 Borislav Petkov 提交于
In order to save on redundant structs definitions insn_get_code_seg_params() was made to return two 4-bit values in a char but clang complains: arch/x86/lib/insn-eval.c:780:10: warning: implicit conversion from 'int' to 'char' changes value from 132 to -124 [-Wconstant-conversion] return INSN_CODE_SEG_PARAMS(4, 8); ~~~~~~ ^~~~~~~~~~~~~~~~~~~~~~~~~~ ./arch/x86/include/asm/insn-eval.h:16:57: note: expanded from macro 'INSN_CODE_SEG_PARAMS' #define INSN_CODE_SEG_PARAMS(oper_sz, addr_sz) (oper_sz | (addr_sz << 4)) Those two values do get picked apart afterwards the opposite way of how they were ORed so wrt to the LSByte, the return value is the same. But this function returns -EINVAL in the error case, which is an int. So make it return an int which is the native word size anyway and thus fix the clang warning. Reported-by: NKees Cook <keescook@google.com> Reported-by: NNick Desaulniers <nick.desaulniers@gmail.com> Signed-off-by: NBorislav Petkov <bp@suse.de> Signed-off-by: NThomas Gleixner <tglx@linutronix.de> Cc: ricardo.neri-calderon@linux.intel.com Link: https://lkml.kernel.org/r/20171123091951.1462-1-bp@alien8.de
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- 21 11月, 2017 1 次提交
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由 Ricardo Neri 提交于
Print a rate-limited warning when a user-space program attempts to execute any of the instructions that UMIP protects (i.e., SGDT, SIDT, SLDT, STR and SMSW). This is useful, because when CONFIG_X86_INTEL_UMIP=y is selected and supported by the hardware, user space programs that try to execute such instructions will receive a SIGSEGV signal that they might not expect. In the specific cases for which emulation is provided (instructions SGDT, SIDT and SMSW in protected and virtual-8086 modes), no signal is generated. However, a warning is helpful to encourage updates in such programs to avoid the use of such instructions. Warnings are printed via a customized printk() function that also provides information about the program that attempted to use the affected instructions. Utility macros are defined to wrap umip_printk() for the error and warning kernel log levels. While here, replace an existing call to the generic rate-limited pr_err() with the new umip_pr_err(). Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NRicardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Tony Luck <tony.luck@intel.com> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1511233476-17088-1-git-send-email-ricardo.neri-calderon@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 14 11月, 2017 1 次提交
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由 Ricardo Neri 提交于
The STR and SLDT instructions are not emulated by the UMIP code, thus there's no functionality in the decoder to identify them. However, a subsequent commit will introduce a warning about the use of all the instructions that UMIP protect/changes, not only those that are emulated. A first step for that is to add the ability to decode/identify them. Plus, now that STR and SLDT are identified, we need to explicitly avoid their emulation (i.e., not rely on successful identification). Group together all the cases that we do not want to emulate: STR, SLDT and user long mode processes. Signed-off-by: NRicardo Neri <ricardo.neri-calderon@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1510640985-18412-4-git-send-email-ricardo.neri-calderon@linux.intel.com [ Rewrote the changelog, fixed ugly col80 artifact. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 08 11月, 2017 2 次提交
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由 Ricardo Neri 提交于
fixup_umip_exception() will be called from do_general_protection(). If the former returns false, the latter will issue a SIGSEGV with SEND_SIG_PRIV. However, when emulation is successful but the emulated result cannot be copied to user space memory, it is more accurate to issue a SIGSEGV with SEGV_MAPERR with the offending address. A new function, inspired in force_sig_info_fault(), is introduced to model the page fault. Signed-off-by: NRicardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-9-git-send-email-ricardo.neri-calderon@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Ricardo Neri 提交于
The feature User-Mode Instruction Prevention present in recent Intel processor prevents a group of instructions (sgdt, sidt, sldt, smsw, and str) from being executed with CPL > 0. Otherwise, a general protection fault is issued. Rather than relaying to the user space the general protection fault caused by the UMIP-protected instructions (in the form of a SIGSEGV signal), it can be trapped and the instruction emulated to provide a dummy result. This allows to both conserve the current kernel behavior and not reveal the system resources that UMIP intends to protect (i.e., the locations of the global descriptor and interrupt descriptor tables, the segment selectors of the local descriptor table, the value of the task state register and the contents of the CR0 register). This emulation is needed because certain applications (e.g., WineHQ and DOSEMU2) rely on this subset of instructions to function. Given that sldt and str are not commonly used in programs that run on WineHQ or DOSEMU2, they are not emulated. Also, emulation is provided only for 32-bit processes; 64-bit processes that attempt to use the instructions that UMIP protects will receive the SIGSEGV signal issued as a consequence of the general protection fault. The instructions protected by UMIP can be split in two groups. Those which return a kernel memory address (sgdt and sidt) and those which return a value (smsw, sldt and str; the last two not emulated). For the instructions that return a kernel memory address, applications such as WineHQ rely on the result being located in the kernel memory space, not the actual location of the table. The result is emulated as a hard-coded value that lies close to the top of the kernel memory. The limit for the GDT and the IDT are set to zero. The instruction smsw is emulated to return the value that the register CR0 has at boot time as set in the head_32. Care is taken to appropriately emulate the results when segmentation is used. That is, rather than relying on USER_DS and USER_CS, the function insn_get_addr_ref() inspects the segment descriptor pointed by the registers in pt_regs. This ensures that we correctly obtain the segment base address and the address and operand sizes even if the user space application uses a local descriptor table. Signed-off-by: NRicardo Neri <ricardo.neri-calderon@linux.intel.com> Reviewed-by: NThomas Gleixner <tglx@linutronix.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Borislav Petkov <bp@suse.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Chen Yucong <slaoub@gmail.com> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Huang Rui <ray.huang@amd.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi V. Shankar <ravi.v.shankar@intel.com> Cc: Shuah Khan <shuah@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: ricardo.neri@intel.com Link: http://lkml.kernel.org/r/1509935277-22138-8-git-send-email-ricardo.neri-calderon@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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