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Fri, 5 Jun 2020 12:21:08 -0400 Received: from [192.168.100.1] ([82.252.135.106]) by mrelayeu.kundenserver.de (mreue107 [213.165.67.119]) with ESMTPSA (Nemesis) id 1MD9CZ-1jqHcy3E8H-00977A; Fri, 05 Jun 2020 18:20:54 +0200 Subject: Re: [PATCH v3] binfmt_misc: pass binfmt_misc flags to the interpreter To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, YunQiang Su , YunQiang Su , Alexander Viro , James Bottomley References: <20200128132539.782286-1-laurent@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: <348e8e7a-3a2c-23b7-4a2e-d3f5e8a62173@vivier.eu> Date: Fri, 5 Jun 2020 18:20:47 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.8.0 MIME-Version: 1.0 In-Reply-To: <20200128132539.782286-1-laurent@vivier.eu> Content-Type: text/plain; charset=utf-8 Content-Language: fr Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:CJWnNS6t81j4qzw3g9XQQQW/Krz79nyKBQKdvfN6saD7FitXX9b 2G6HkpgZuWObozbs2/Ob6IN4lAZJijGyWrceUxPADueFeCQ0WC5brR+O6eKuRzDdh76krEa UmM2XvZIg+PMRHhuB9QoGt867etu3+R4nddb0BVYGT2HGIruzK0KHX3h32Jyd7lzeAn9WuA QrIf+X+SzEIBcj5Xox7TQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:wTOXGu8jl64=:cR1ZJv0JIVxdlx/KmO2ALK X9hI6f8SZ58pdTz6cj8A7GWAAtHvbiAEpPP5oalNeajGFD3detXNBmarJJ4pilOeBsVC9opIx Oeb96D36r50s3aNXKdvcEFkvEdR7OEAY3p8ILtt4Lv7JMWIQsCSm7/zB2UhR4NXGsNgKn+xNr kDt1FBokoBQDn64MvA3wgpXsMtxlPfrvku6ShmnLKUa2MdUcF6FRvnYRiRyHs1tkW6sxNOfg9 9anY9sgbqPjxfpo3BdjWX5WIS2UbXsGAA0wJhtocF1BazdxpkGtjEAge8HNVgZf+61XieYXnY dh/sBoWHpNN7E4Hq5rQJcjdn4bWjAIDNLEK2axpoGgUwKpVKdS1/IfhYQ6JPzx94/PeO3uoQ8 akOPYo0ZsvTNqiit+/niNBfFFzsp/NP+tCJo9HOHsHECRZDaGLgGYDYfx6AFr/hKhEmdpZSA4 A7Y4LF807erHNZKILvspy2mzAsj3fivbeInVSxmvLAhTztwl8MtJAysdiCg492QUZGhV8d1Jx Nl8afVoqLMYdJeAHL560oVPC8nmoQWabftnDyZThq7NX0BkqsB2EuIdkXcvR1V298U0w/TJfH +qek6zt7ed2ZYiDLoy+R2IZ0p3gKGKNPkUWXNCJUuQn8+71ooIOP33X9Km5JjcpAdIkCifK/V ISdaRB53bXQYWSTk7ry6upVVLRxVPNAxicXA3W8EmXL/TcUpa1d4GjBfCQYm80H9NFdgqYC1f 72iYNZJ0EWqAui5thFvuKV636ysMtp9tlErCjcc293Nw44n4M4fMy/Ls1Opj3IV1HQBK3xQok GJOm5G7uCqMVP1VXEIH1yzF+ZfCu1A5R6IdfVZ67Bj549HPV0cRJiH2/2VcYPgR4GPQ62ZL Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Ping? Thanks, Laurent Le 28/01/2020 à 14:25, Laurent Vivier a écrit : > It can be useful to the interpreter to know which flags are in use. > > For instance, knowing if the preserve-argv[0] is in use would > allow to skip the pathname argument. > > This patch uses an unused auxiliary vector, AT_FLAGS, to add a > flag to inform interpreter if the preserve-argv[0] is enabled. > > Signed-off-by: Laurent Vivier > --- > > Notes: > This can be tested with QEMU from my branch: > > https://github.com/vivier/qemu/commits/binfmt-argv0 > > With something like: > > # cp ..../qemu-ppc /chroot/powerpc/jessie > > # qemu-binfmt-conf.sh --qemu-path / --systemd ppc --credential yes \ > --persistent no --preserve-argv0 yes > # systemctl restart systemd-binfmt.service > # cat /proc/sys/fs/binfmt_misc/qemu-ppc > enabled > interpreter //qemu-ppc > flags: POC > offset 0 > magic 7f454c4601020100000000000000000000020014 > mask ffffffffffffff00fffffffffffffffffffeffff > # chroot /chroot/powerpc/jessie sh -c 'echo $0' > sh > > # qemu-binfmt-conf.sh --qemu-path / --systemd ppc --credential yes \ > --persistent no --preserve-argv0 no > # systemctl restart systemd-binfmt.service > # cat /proc/sys/fs/binfmt_misc/qemu-ppc > enabled > interpreter //qemu-ppc > flags: OC > offset 0 > magic 7f454c4601020100000000000000000000020014 > mask ffffffffffffff00fffffffffffffffffffeffff > # chroot /chroot/powerpc/jessie sh -c 'echo $0' > /bin/sh > > v3: mix my patch with one from YunQiang Su and my comments on it > introduce a new flag in the uabi for the AT_FLAGS > v2: only pass special flags (remove Magic and Enabled flags) > > fs/binfmt_elf.c | 5 ++++- > fs/binfmt_elf_fdpic.c | 5 ++++- > fs/binfmt_misc.c | 4 +++- > include/linux/binfmts.h | 4 ++++ > include/uapi/linux/binfmts.h | 4 ++++ > 5 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index ecd8d2698515..ff918042ceed 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -176,6 +176,7 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec, > unsigned char k_rand_bytes[16]; > int items; > elf_addr_t *elf_info; > + elf_addr_t flags = 0; > int ei_index = 0; > const struct cred *cred = current_cred(); > struct vm_area_struct *vma; > @@ -250,7 +251,9 @@ create_elf_tables(struct linux_binprm *bprm, 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 |= AT_FLAGS_PRESERVE_ARGV0; > + NEW_AUX_ENT(AT_FLAGS, flags); > NEW_AUX_ENT(AT_ENTRY, exec->e_entry); > NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid)); > NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid)); > diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c > index 240f66663543..abb90d82aa58 100644 > --- a/fs/binfmt_elf_fdpic.c > +++ b/fs/binfmt_elf_fdpic.c > @@ -507,6 +507,7 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, > char __user *u_platform, *u_base_platform, *p; > int loop; > int nr; /* reset for each csp adjustment */ > + unsigned long flags = 0; > > #ifdef CONFIG_MMU > /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions > @@ -647,7 +648,9 @@ static int create_elf_fdpic_tables(struct linux_binprm *bprm, > NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr)); > NEW_AUX_ENT(AT_PHNUM, exec_params->hdr.e_phnum); > NEW_AUX_ENT(AT_BASE, interp_params->elfhdr_addr); > - NEW_AUX_ENT(AT_FLAGS, 0); > + if (bprm->interp_flags & BINPRM_FLAGS_PRESERVE_ARGV0) > + flags |= AT_FLAGS_PRESERVE_ARGV0; > + NEW_AUX_ENT(AT_FLAGS, flags); > NEW_AUX_ENT(AT_ENTRY, exec_params->entry_addr); > NEW_AUX_ENT(AT_UID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->uid)); > NEW_AUX_ENT(AT_EUID, (elf_addr_t) from_kuid_munged(cred->user_ns, cred->euid)); > diff --git a/fs/binfmt_misc.c b/fs/binfmt_misc.c > index cdb45829354d..b9acdd26a654 100644 > --- a/fs/binfmt_misc.c > +++ b/fs/binfmt_misc.c > @@ -154,7 +154,9 @@ static int load_misc_binary(struct linux_binprm *bprm) > if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) > goto ret; > > - if (!(fmt->flags & MISC_FMT_PRESERVE_ARGV0)) { > + if (fmt->flags & MISC_FMT_PRESERVE_ARGV0) { > + bprm->interp_flags |= BINPRM_FLAGS_PRESERVE_ARGV0; > + } else { > retval = remove_arg_zero(bprm); > if (retval) > goto ret; > diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h > index b40fc633f3be..265b80d5fd6f 100644 > --- a/include/linux/binfmts.h > +++ b/include/linux/binfmts.h > @@ -78,6 +78,10 @@ struct linux_binprm { > #define BINPRM_FLAGS_PATH_INACCESSIBLE_BIT 2 > #define BINPRM_FLAGS_PATH_INACCESSIBLE (1 << BINPRM_FLAGS_PATH_INACCESSIBLE_BIT) > > +/* if preserve the argv0 for the interpreter */ > +#define BINPRM_FLAGS_PRESERVE_ARGV0_BIT 3 > +#define BINPRM_FLAGS_PRESERVE_ARGV0 (1 << BINPRM_FLAGS_PRESERVE_ARGV0_BIT) > + > /* Function parameter for binfmt->coredump */ > struct coredump_params { > const kernel_siginfo_t *siginfo; > diff --git a/include/uapi/linux/binfmts.h b/include/uapi/linux/binfmts.h > index 689025d9c185..a70747416130 100644 > --- a/include/uapi/linux/binfmts.h > +++ b/include/uapi/linux/binfmts.h > @@ -18,4 +18,8 @@ struct pt_regs; > /* sizeof(linux_binprm->buf) */ > #define BINPRM_BUF_SIZE 256 > > +/* if preserve the argv0 for the interpreter */ > +#define AT_FLAGS_PRESERVE_ARGV0_BIT 0 > +#define AT_FLAGS_PRESERVE_ARGV0 (1 << AT_FLAGS_PRESERVE_ARGV0_BIT) > + > #endif /* _UAPI_LINUX_BINFMTS_H */ >