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Thu, 16 Jan 2020 03:19:14 -0500 Received: from [192.168.100.1] ([78.238.229.36]) by mrelayeu.kundenserver.de (mreue106 [213.165.67.119]) with ESMTPSA (Nemesis) id 1MCJvA-1ijn9g2WJO-009Pbj; Thu, 16 Jan 2020 09:19:02 +0100 Subject: Re: [PATCH v2] binfmt_misc: pass info about P flag by AT_FLAGS To: YunQiang Su Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, James Bottomley , Al Viro , YunQiang Su References: <20200116022049.164659-1-syq@debian.org> <7af5c24d-dd24-b728-92cf-a5a759787590@vivier.eu> From: Laurent Vivier Autocrypt: addr=laurent@vivier.eu; prefer-encrypt=mutual; keydata= mQINBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABtCJMYXVyZW50IFZp dmllciA8bGF1cmVudEB2aXZpZXIuZXU+iQI4BBMBAgAiBQJWBTDeAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRDzDDi9Py++PCEdD/oD8LD5UWxhQrMQCsUgLlXCSM7sxGLkwmmF ozqSSljEGRhffxZvO35wMFcdX9Z0QOabVoFTKrT04YmvbjsErh/dP5zeM/4EhUByeOS7s6Yl HubMXVQTkak9Wa9Eq6irYC6L41QNzz/oTwNEqL1weV1+XC3TNnht9B76lIaELyrJvRfgsp9M rE+PzGPo5h7QHWdL/Cmu8yOtPLa8Y6l/ywEJ040IoiAUfzRoaJs2csMXf0eU6gVBhCJ4bs91 jtWTXhkzdl4tdV+NOwj3j0ukPy+RjqeL2Ej+bomnPTOW8nAZ32dapmu7Fj7VApuQO/BSIHyO NkowMMjB46yohEepJaJZkcgseaus0x960c4ua/SUm/Nm6vioRsxyUmWd2nG0m089pp8LPopq WfAk1l4GciiMepp1Cxn7cnn1kmG6fhzedXZ/8FzsKjvx/aVeZwoEmucA42uGJ3Vk9TiVdZes lqMITkHqDIpHjC79xzlWkXOsDbA2UY/P18AtgJEZQPXbcrRBtdSifCuXdDfHvI+3exIdTpvj BfbgZAar8x+lcsQBugvktlQWPfAXZu4Shobi3/mDYMEDOE92dnNRD2ChNXg2IuvAL4OW40wh gXlkHC1ZgToNGoYVvGcZFug1NI+vCeCFchX+L3bXyLMg3rAfWMFPAZLzn42plIDMsBs+x2yP +bkCDQRWBSYZARAAvFJBFuX9A6eayxUPFaEczlMbGXugs0mazbOYGlyaWsiyfyc3PStHLFPj rSTaeJpPCjBJErwpZUN4BbpkBpaJiMuVO6egrC8Xy8/cnJakHPR2JPEvmj7Gm/L9DphTcE15 92rxXLesWzGBbuYxKsj8LEnrrvLyi3kNW6B5LY3Id+ZmU8YTQ2zLuGV5tLiWKKxc6s3eMXNq wrJTCzdVd6ThXrmUfAHbcFXOycUyf9vD+s+WKpcZzCXwKgm7x1LKsJx3UhuzT8ier1L363RW ZaJBZ9CTPiu8R5NCSn9V+BnrP3wlFbtLqXp6imGhazT9nJF86b5BVKpF8Vl3F0/Y+UZ4gUwL d9cmDKBcmQU/JaRUSWvvolNu1IewZZu3rFSVgcpdaj7F/1aC0t5vLdx9KQRyEAKvEOtCmP4m 38kU/6r33t3JuTJnkigda4+Sfu5kYGsogeYG6dNyjX5wpK5GJIJikEhdkwcLM+BUOOTi+I9u tX03BGSZo7FW/J7S9y0l5a8nooDs2gBRGmUgYKqQJHCDQyYut+hmcr+BGpUn9/pp2FTWijrP inb/Pc96YDQLQA1q2AeAFv3Rx3XoBTGl0RCY4KZ02c0kX/dm3eKfMX40XMegzlXCrqtzUk+N 8LeipEsnOoAQcEONAWWo1HcgUIgCjhJhBEF0AcELOQzitbJGG5UAEQEAAYkCHwQYAQIACQUC VgUmGQIbDAAKCRDzDDi9Py++PCD3D/9VCtydWDdOyMTJvEMRQGbx0GacqpydMEWbE3kUW0ha US5jz5gyJZHKR3wuf1En/3z+CEAEfP1M3xNGjZvpaKZXrgWaVWfXtGLoWAVTfE231NMQKGoB w2Dzx5ivIqxikXB6AanBSVpRpoaHWb06tPNxDL6SVV9lZpUn03DSR6gZEZvyPheNWkvz7bE6 FcqszV/PNvwm0C5Ju7NlJA8PBAQjkIorGnvN/vonbVh5GsRbhYPOc/JVwNNr63P76rZL8Gk/ hb3xtcIEi5CCzab45+URG/lzc6OV2nTj9Lg0SNcRhFZ2ILE3txrmI+aXmAu26+EkxLLfqCVT ohb2SffQha5KgGlOSBXustQSGH0yzzZVZb+HZPEvx6d/HjQ+t9sO1bCpEgPdZjyMuuMp9N1H ctbwGdQM2Qb5zgXO+8ZSzwC+6rHHIdtcB8PH2j+Nd88dVGYlWFKZ36ELeZxD7iJflsE8E8yg OpKgu3nD0ahBDqANU/ZmNNarBJEwvM2vfusmNnWm3QMIwxNuJghRyuFfx694Im1js0ZY3LEU JGSHFG4ZynA+ZFUPA6Xf0wHeJOxGKCGIyeKORsteIqgnkINW9fnKJw2pgk8qHkwVc3Vu+wGS ZiJK0xFusPQehjWTHn9WjMG1zvQ5TQQHxau/2FkP45+nRPco6vVFQe8JmgtRF8WFJA== Message-ID: Date: Thu, 16 Jan 2020 09:18:59 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: fr Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:5gekEDFq6ApMxdo31EQO60DK7ecvC29vrFCg7fqkyJ+zYysBube EQp7lW8LyhYv76QADEzx6PYIAw83sXQblbzHFyJkfU+/VolHIX2JVL0TsSjQhbR0FID/5v+ /gXuTFyEmnCMa6ZowrmiatfMxtZF3Z6lCT84B5r8dDeGKL+BcBLfDhQmv0EXhdfxlDI8uTN Gc4rtn/5sIwP6oHnPtiIg== X-UI-Out-Filterresults: notjunk:1;V03:K0:4YSYlm/zXA4=:/eDQLBj82Lwx9VbR5sdGLD pcWWeQ4bDgoWiRTf5Q1EiQmA1VC4uXu4Y49IxwYMt1GAuOnvJHXzMOeLFC7c5Scqw2XpA36Ge kYDCS+UvZUa0PhObL2OgK8mHGvRBnArimpa5sVaOp54qOvGzKmWGGyha8iAOXQKuDbqNBwBnd 3Xe4vLbxNhaQy9FVSO2hJ9GFm2Q3IJe0a7zcTihaARTGjm5K4GGNwFOysDXk1kMiwyDoJGkCL IQ2xUduL9zUwUUbhL9+Xg4bakcpQIQeuEdXxsDz6xYKvRBJiBYQCj8SBaVXF06dpcY5AI7qGe Z0J9TvzmF+urp9pxGoYSRAEY0/UAlh/MxRYpVQp1TQtM3IVDXnfnD1Gl8uVtbVQ5RWVt0SyQI igYNeDfQgAdk+7/cTY53gDH/iUyDUZCzJXZqfdrwPYtYl3o+YknZSl8Icn7Sum6hZCBXKbx0A wW4KH0YUNFBIbj0/h3X83ISQtPZCcgZp6Xyw2QX/E0ttBLN84UM92DcMgUghvfTirsEO2R2Zc 9TZKSgmR7tbfnHr0P5CL2CcyblXYwavFbjlRH4TqqBdZRKZlJI9UQINd9ug3XJitCcTygifpX 87C5ROypcGt3Ikuz6+gZthHk9uw1dj058SGjVjNcZ83Y+S/WyB3o51RGyOx01uE442dug715H okliyOsan606lQyKuBiicPQ7nWmZBkHiSRFhZke6tqEdlmDG0Hk3cVFNrwTXg88lJw1JUJ4Vs A5C55l2hNn20AqZsd5V0Rl5nUgaapZmpV4/jFg3z0RL24KoHxoD0n4q8mPSrBnv138NsEhk/S mKaXcJ89BQ2jGBL7tZUbLFuVRCNDDTxy30fLOLY5qj9nnoDcSys0NrtjaL2HlMzdhyFbG9vxs 7gvcGXv8ZdgGBuNKWkT7F047r6SAyQQzr+eYhHI8jUSQkRRK3br9AWgo8KXoIz9HDA5QaZIp/ s8Jzsh3hrNOC6aGB/8IaVZdlr/QacUlV9Orvv+tssm6UB3xzhbOMMg1AI8ctcaMSjzLoXnxnH pv9IsMeG3pstC8kBPjo1fbHELachBsyfzgDIWqdr1OtY Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 16/01/2020 à 09:17, YunQiang Su a écrit : > Laurent Vivier 于2020年1月16日周四 下午4:07写道： >> >> Le 16/01/2020 à 03:20, YunQiang Su a écrit : >>> From: YunQiang Su >>> >>> Currently program invoked by binfmt_misc cannot be aware about whether >>> P flag, aka preserve path is enabled. >>> >>> Some applications like qemu need to know since it has 2 use case: >>> 1. call by hand, like: qemu-mipsel-static test.app OPTION >>> so, qemu have to assume that P option is not enabled. >>> 2. call by binfmt_misc. If qemu cannot know about whether P flag is >>> enabled, distribution's have to set qemu without P flag, and >>> binfmt_misc call qemu like: >>> qemu-mipsel-static /absolute/path/to/test.app OPTION >>> even test.app is not called by absoulute path, like >>> ./relative/path/to/test.app >>> >>> This patch passes this information by the 3rd bits of unused AT_FLAGS. >>> Then, in qemu, we can get this info by: >>> getauxval(AT_FLAGS) & (1<<3) >>> >>> v1->v2: >>> not enable kdebug >>> >>> See: https://bugs.launchpad.net/qemu/+bug/1818483 >>> Signed-off-by: YunQiang Su >>> --- >>> fs/binfmt_elf.c | 6 +++++- >>> fs/binfmt_elf_fdpic.c | 6 +++++- >>> fs/binfmt_misc.c | 2 ++ >>> include/linux/binfmts.h | 4 ++++ >>> 4 files changed, 16 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c >>> index f4713ea76e82..d33ee07d7f57 100644 >>> --- a/fs/binfmt_elf.c >>> +++ b/fs/binfmt_elf.c >>> @@ -178,6 +178,7 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, >>> unsigned char k_rand_bytes[16]; >>> int items; >>> elf_addr_t *elf_info; >>> + elf_addr_t flags = 0; >>> int ei_index; >>> const struct cred *cred = current_cred(); >>> struct vm_area_struct *vma; >>> @@ -252,7 +253,10 @@ create_elf_tables(struct linux_binprm *bprm, const struct elfhdr *exec, >>> NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr)); >>> NEW_AUX_ENT(AT_PHNUM, exec->e_phnum); >>> NEW_AUX_ENT(AT_BASE, interp_load_addr); >>> - NEW_AUX_ENT(AT_FLAGS, 0); >>> + if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0) { >>> + flags |= BINPRM_FLAGS_PRESERVE_ARGV0; >>> + } >> >> Perhaps we also need a different flag in AT_FLAG than in interp_flag as >> BINPRM_FLAGS_PRESERVE_ARGV0 is also part of the internal ABI? > > yep. It may be really a problem. > So, should we define a set of new macros for AT_FLAGS? Yes, I think. Thanks, Laurent