Hi! Oops, sorry, I've been behind on the execve/binfmt tree reviews. I'll put this in my tree for -next now. Thanks for the poke! -Kees On Mon, Apr 22, 2024 at 03:01:32PM -0700, Andrew Morton wrote: > > The patch titled > Subject: binfmt_elf_fdpic: fix /proc/<pid>/auxv > has been added to the -mm mm-nonmm-unstable branch. Its filename is > binfmt_elf_fdpic-fix-proc-pid-auxv.patch > > This patch will shortly appear at > https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/binfmt_elf_fdpic-fix-proc-pid-auxv.patch > > This patch will later appear in the mm-nonmm-unstable branch at > git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > > Before you just go and hit "reply", please: > a) Consider who else should be cc'ed > b) Prefer to cc a suitable mailing list as well > c) Ideally: find the original patch on the mailing list and do a > reply-to-all to that, adding suitable additional cc's > > *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** > > The -mm tree is included into linux-next via the mm-everything > branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm > and is updated there every 2-3 working days > > ------------------------------------------------------ > From: Max Filippov <jcmvbkbc@xxxxxxxxx> > Subject: binfmt_elf_fdpic: fix /proc/<pid>/auxv > Date: Fri, 22 Mar 2024 12:54:18 -0700 > > Althought FDPIC linux kernel provides /proc/<pid>/auxv files they are > empty because there's no code that initializes mm->saved_auxv in the FDPIC > ELF loader. > > Synchronize FDPIC ELF aux vector setup with ELF. Replace entry-by-entry > aux vector copying to userspace with initialization of mm->saved_auxv > first and then copying it to userspace as a whole. > > Link: https://lkml.kernel.org/r/20240322195418.2160164-1-jcmvbkbc@xxxxxxxxx > Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx> > Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> > Cc: Christian Brauner <brauner@xxxxxxxxxx> > Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> > Cc: Jan Kara <jack@xxxxxxx> > Cc: Kees Cook <keescook@xxxxxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > --- > > fs/binfmt_elf_fdpic.c | 90 +++++++++++++++++++--------------------- > 1 file changed, 43 insertions(+), 47 deletions(-) > > --- a/fs/binfmt_elf_fdpic.c~binfmt_elf_fdpic-fix-proc-pid-auxv > +++ a/fs/binfmt_elf_fdpic.c > @@ -505,8 +505,9 @@ static int create_elf_fdpic_tables(struc > char *k_platform, *k_base_platform; > char __user *u_platform, *u_base_platform, *p; > int loop; > - int nr; /* reset for each csp adjustment */ > unsigned long flags = 0; > + int ei_index; > + elf_addr_t *elf_info; > > #ifdef CONFIG_MMU > /* In some cases (e.g. Hyper-Threading), we want to avoid L1 evictions > @@ -601,44 +602,24 @@ static int create_elf_fdpic_tables(struc > csp -= sp & 15UL; > sp -= sp & 15UL; > > - /* put the ELF interpreter info on the stack */ > -#define NEW_AUX_ENT(id, val) \ > - do { \ > - struct { unsigned long _id, _val; } __user *ent, v; \ > - \ > - ent = (void __user *) csp; \ > - v._id = (id); \ > - v._val = (val); \ > - if (copy_to_user(ent + nr, &v, sizeof(v))) \ > - return -EFAULT; \ > - nr++; \ > + /* Create the ELF interpreter info */ > + elf_info = (elf_addr_t *)mm->saved_auxv; > + /* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */ > +#define NEW_AUX_ENT(id, val) \ > + do { \ > + *elf_info++ = id; \ > + *elf_info++ = val; \ > } while (0) > > - nr = 0; > - csp -= 2 * sizeof(unsigned long); > - NEW_AUX_ENT(AT_NULL, 0); > - if (k_platform) { > - nr = 0; > - csp -= 2 * sizeof(unsigned long); > - NEW_AUX_ENT(AT_PLATFORM, > - (elf_addr_t) (unsigned long) u_platform); > - } > - > - if (k_base_platform) { > - nr = 0; > - csp -= 2 * sizeof(unsigned long); > - NEW_AUX_ENT(AT_BASE_PLATFORM, > - (elf_addr_t) (unsigned long) u_base_platform); > - } > - > - if (bprm->have_execfd) { > - nr = 0; > - csp -= 2 * sizeof(unsigned long); > - NEW_AUX_ENT(AT_EXECFD, bprm->execfd); > - } > - > - nr = 0; > - csp -= DLINFO_ITEMS * 2 * sizeof(unsigned long); > +#ifdef ARCH_DLINFO > + /* > + * ARCH_DLINFO must come first so PPC can do its special alignment of > + * AUXV. > + * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in > + * ARCH_DLINFO changes > + */ > + ARCH_DLINFO; > +#endif > NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP); > #ifdef ELF_HWCAP2 > NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2); > @@ -659,17 +640,32 @@ static int create_elf_fdpic_tables(struc > NEW_AUX_ENT(AT_EGID, (elf_addr_t) from_kgid_munged(cred->user_ns, cred->egid)); > NEW_AUX_ENT(AT_SECURE, bprm->secureexec); > NEW_AUX_ENT(AT_EXECFN, bprm->exec); > - > -#ifdef ARCH_DLINFO > - nr = 0; > - csp -= AT_VECTOR_SIZE_ARCH * 2 * sizeof(unsigned long); > - > - /* ARCH_DLINFO must come last so platform specific code can enforce > - * special alignment requirements on the AUXV if necessary (eg. PPC). > - */ > - ARCH_DLINFO; > -#endif > + if (k_platform) { > + NEW_AUX_ENT(AT_PLATFORM, > + (elf_addr_t)(unsigned long)u_platform); > + } > + if (k_base_platform) { > + NEW_AUX_ENT(AT_BASE_PLATFORM, > + (elf_addr_t)(unsigned long)u_base_platform); > + } > + if (bprm->have_execfd) { > + NEW_AUX_ENT(AT_EXECFD, bprm->execfd); > + } > #undef NEW_AUX_ENT > + /* AT_NULL is zero; clear the rest too */ > + memset(elf_info, 0, (char *)mm->saved_auxv + > + sizeof(mm->saved_auxv) - (char *)elf_info); > + > + /* And advance past the AT_NULL entry. */ > + elf_info += 2; > + > + ei_index = elf_info - (elf_addr_t *)mm->saved_auxv; > + csp -= ei_index * sizeof(elf_addr_t); > + > + /* Put the elf_info on the stack in the right place. */ > + if (copy_to_user((void __user *)csp, mm->saved_auxv, > + ei_index * sizeof(elf_addr_t))) > + return -EFAULT; > > /* allocate room for argv[] and envv[] */ > csp -= (bprm->envc + 1) * sizeof(elf_caddr_t); > _ > > Patches currently in -mm which might be from jcmvbkbc@xxxxxxxxx are > > binfmt_elf_fdpic-fix-proc-pid-auxv.patch > -- Kees Cook
