user/sven/linux.git/scripts/mod/modpost.c, branch v4.9.319

modpost: fix undefined behavior of is_arm_mapping_symbol()

2022-06-14T14:52:40Z

[ Upstream commit d6b732666a1bae0df3c3ae06925043bba34502b1 ] The return value of is_arm_mapping_symbol() is unpredictable when "$" is passed in. strchr(3) says: The strchr() and strrchr() functions return a pointer to the matched character or NULL if the character is not found. The terminating null byte is considered part of the string, so that if c is specified as '\0', these functions return a pointer to the terminator. When str[1] is '\0', strchr("axtd", str[1]) is not NULL, and str[2] is referenced (i.e. buffer overrun). Test code --------- char str1[] = "abc"; char str2[] = "ab"; strcpy(str1, "$"); strcpy(str2, "$"); printf("test1: %d\n", is_arm_mapping_symbol(str1)); printf("test2: %d\n", is_arm_mapping_symbol(str2)); Result ------ test1: 0 test2: 1 Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers Signed-off-by: Sasha Levin

modpost: fix removing numeric suffixes

2022-06-14T14:52:38Z

[ Upstream commit b5beffa20d83c4e15306c991ffd00de0d8628338 ] With the `-z unique-symbol` linker flag or any similar mechanism, it is possible to trigger the following: ERROR: modpost: "param_set_uint.0" [vmlinux] is a static EXPORT_SYMBOL The reason is that for now the condition from remove_dot(): if (m && (s[n + m] == '.' || s[n + m] == 0)) which was designed to test if it's a dot or a '\0' after the suffix is never satisfied. This is due to that `s[n + m]` always points to the last digit of a numeric suffix, not on the symbol next to it (from a custom debug print added to modpost): param_set_uint.0, s[n + m] is '0', s[n + m + 1] is '\0' So it's off-by-one and was like that since 2014. Fix this for the sake of any potential upcoming features, but don't bother stable-backporting, as it's well hidden -- apart from that LD flag, it can be triggered only with GCC LTO which never landed upstream. Fixes: fcd38ed0ff26 ("scripts: modpost: fix compilation warning") Signed-off-by: Alexander Lobakin Reviewed-by: Petr Mladek Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

x86, modpost: Replace last remnants of RETPOLINE with CONFIG_RETPOLINE

2022-03-11T09:03:32Z

commit e4f358916d528d479c3c12bd2fd03f2d5a576380 upstream. Commit 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") replaced the RETPOLINE define with CONFIG_RETPOLINE checks. Remove the remaining pieces. [ bp: Massage commit message. ] Fixes: 4cd24de3a098 ("x86/retpoline: Make CONFIG_RETPOLINE depend on compiler support") Signed-off-by: WANG Chao Signed-off-by: Borislav Petkov Reviewed-by: Zhenzhong Duan Reviewed-by: Masahiro Yamada Cc: "H. Peter Anvin" Cc: Andi Kleen Cc: Andrew Morton Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Daniel Borkmann Cc: David Woodhouse Cc: Geert Uytterhoeven Cc: Jessica Yu Cc: Jiri Kosina Cc: Kees Cook Cc: Konrad Rzeszutek Wilk Cc: Luc Van Oostenryck Cc: Michal Marek Cc: Miguel Ojeda Cc: Peter Zijlstra Cc: Tim Chen Cc: Vasily Gorbik Cc: linux-kbuild@vger.kernel.org Cc: srinivas.eeda@oracle.com Cc: stable Cc: x86-ml Link: https://lkml.kernel.org/r/20181210163725.95977-1-chao.wang@ucloud.cn [bwh: Backported to 4.9: adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

modpost: skip ELF local symbols during section mismatch check

2019-12-21T09:41:17Z

[ Upstream commit a4d26f1a0958bb1c2b60c6f1e67c6f5d43e2647b ] During development of a serial console driver with a gcc 8.2.0 toolchain for RISC-V, the following modpost warning appeared: ---- WARNING: vmlinux.o(.data+0x19b10): Section mismatch in reference from the variable .LANCHOR1 to the function .init.text:sifive_serial_console_setup() The variable .LANCHOR1 references the function __init sifive_serial_console_setup() If the reference is valid then annotate the variable with __init* or __refdata (see linux/init.h) or name the variable: *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console ---- ".LANCHOR1" is an ELF local symbol, automatically created by gcc's section anchor generation code: https://gcc.gnu.org/onlinedocs/gccint/Anchored-Addresses.html https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/varasm.c;h=cd9591a45617464946dcf9a126dde277d9de9804;hb=9fb89fa845c1b2e0a18d85ada0b077c84508ab78#l7473 This was verified by compiling the kernel with -fno-section-anchors and observing that the ".LANCHOR1" ELF local symbol disappeared, and modpost no longer warned about the section mismatch. The serial driver code idiom triggering the warning is standard Linux serial driver practice that has a specific whitelist inclusion in modpost.c. I'm neither a modpost nor an ELF expert, but naively, it doesn't seem useful for modpost to report section mismatch warnings caused by ELF local symbols by default. Local symbols have compiler-generated names, and thus bypass modpost's whitelisting algorithm, which relies on the presence of a non-autogenerated symbol name. This increases the likelihood that false positive warnings will be generated (as in the above case). Thus, disable section mismatch reporting on ELF local symbols. The rationale here is similar to that of commit 2e3a10a1551d ("ARM: avoid ARM binutils leaking ELF local symbols") and of similar code already present in modpost.c: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/mod/modpost.c?h=v4.19-rc4&id=7876320f88802b22d4e2daf7eb027dd14175a0f8#n1256 This third version of the patch implements a suggestion from Masahiro Yamada to restructure the code as an additional pattern matching step inside secref_whitelist(), and further improves the patch description. Signed-off-by: Paul Walmsley Signed-off-by: Paul Walmsley Acked-by: Sam Ravnborg Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

modpost: validate symbol names also in find_elf_symbol

2019-02-12T18:44:52Z

[ Upstream commit 5818c683a619c534c113e1f66d24f636defc29bc ] If an ARM mapping symbol shares an address with a valid symbol, find_elf_symbol can currently return the mapping symbol instead, as the symbol is not validated. This can result in confusing warnings: WARNING: vmlinux.o(.text+0x18f4028): Section mismatch in reference from the function set_reset_devices() to the variable .init.text:$x.0 This change adds a call to is_valid_name to find_elf_symbol, similarly to how it's already used in find_elf_symbol2. Signed-off-by: Sami Tolvanen Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin

scripts: modpost: check memory allocation results

2018-09-15T07:42:57Z

[ Upstream commit 1f3aa9002dc6a0d59a4b599b4fc8f01cf43ef014 ] Fix missing error check for memory allocation functions in scripts/mod/modpost.c. Fixes kernel bugzilla #200319: https://bugzilla.kernel.org/show_bug.cgi?id=200319 Signed-off-by: Randy Dunlap Cc: Yuexing Wang Signed-off-by: Masahiro Yamada Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

module/retpoline: Warn about missing retpoline in module

2018-02-13T11:35:58Z

(cherry picked from commit caf7501a1b4ec964190f31f9c3f163de252273b8) There's a risk that a kernel which has full retpoline mitigations becomes vulnerable when a module gets loaded that hasn't been compiled with the right compiler or the right option. To enable detection of that mismatch at module load time, add a module info string "retpoline" at build time when the module was compiled with retpoline support. This only covers compiled C source, but assembler source or prebuilt object files are not checked. If a retpoline enabled kernel detects a non retpoline protected module at load time, print a warning and report it in the sysfs vulnerability file. [ tglx: Massaged changelog ] Signed-off-by: Andi Kleen Signed-off-by: Thomas Gleixner Cc: David Woodhouse Cc: gregkh@linuxfoundation.org Cc: torvalds@linux-foundation.org Cc: jeyu@kernel.org Cc: arjan@linux.intel.com Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@firstfloor.org Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

objtool, modules: Discard objtool annotation sections for modules

2018-01-17T08:38:58Z

commit e390f9a9689a42f477a6073e2e7df530a4c1b740 upstream. The '__unreachable' and '__func_stack_frame_non_standard' sections are only used at compile time. They're discarded for vmlinux but they should also be discarded for modules. Since this is a recurring pattern, prefix the section names with ".discard.". It's a nice convention and vmlinux.lds.h already discards such sections. Also remove the 'a' (allocatable) flag from the __unreachable section since it doesn't make sense for a discarded section. Suggested-by: Linus Torvalds Signed-off-by: Josh Poimboeuf Cc: Jessica Yu Cc: Peter Zijlstra Cc: Thomas Gleixner Fixes: d1091c7fa3d5 ("objtool: Improve detection of BUG() and other dead ends") Link: http://lkml.kernel.org/r/20170301180444.lhd53c5tibc4ns77@treble Signed-off-by: Ingo Molnar [dwmw2: Remove the unreachable part in backporting since it's not here yet] Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman

nmi_backtrace: generate one-line reports for idle cpus

2016-10-08T01:46:30Z

When doing an nmi backtrace of many cores, most of which are idle, the output is a little overwhelming and very uninformative. Suppress messages for cpus that are idling when they are interrupted and just emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". We do this by grouping all the cpuidle code together into a new .cpuidle.text section, and then checking the address of the interrupted PC to see if it lies within that section. This commit suitably tags x86 and tile idle routines, and only adds in the minimal framework for other architectures. Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com Signed-off-by: Chris Metcalf Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Tested-by: Daniel Thompson [arm] Tested-by: Petr Mladek Cc: Aaron Tomlin Cc: Peter Zijlstra (Intel) Cc: "Rafael J. Wysocki" Cc: Russell King Cc: Thomas Gleixner Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

powerpc: Simplify module TOC handling

2016-01-21T03:10:56Z

PowerPC64 uses the symbol .TOC. much as other targets use _GLOBAL_OFFSET_TABLE_. It identifies the value of the GOT pointer (or in powerpc parlance, the TOC pointer). Global offset tables are generally local to an executable or shared library, or in the kernel, module. Thus it does not make sense for a module to resolve a relocation against .TOC. to the kernel's .TOC. value. A module has its own .TOC., and indeed the powerpc64 module relocation processing ignores the kernel value of .TOC. and instead calculates a module-local value. This patch removes code involved in exporting the kernel .TOC., tweaks modpost to ignore an undefined .TOC., and the module loader to twiddle the section symbol so that .TOC. isn't seen as undefined. Note that if the kernel was compiled with -msingle-pic-base then ELFv2 would not have function global entry code setting up r2. In that case the module call stubs would need to be modified to set up r2 using the kernel .TOC. value, requiring some of this code to be reinstated. mpe: Furthermore a change in binutils master (not yet released) causes the current way we handle the TOC to no longer work when building with MODVERSIONS=y and RELOCATABLE=n. The symptom is that modules can not be loaded due to there being no version found for TOC. Cc: stable@vger.kernel.org # 3.16+ Signed-off-by: Alan Modra Signed-off-by: Michael Ellerman