On 4/20/22 23:58, Eric W. Biederman wrote: > Nit: extra blank line here. > In a recent discussion[1] it was reported that the binfmt_flat library > support was only ever used on m68k and even on m68k has not been used > in a very long time. > > The structure of binfmt_flat is different from all of the other binfmt > implementations becasue of this shared library support and it made s/becasue/because > life and code review more effort when I refactored the code in fs/exec.c. > > Since in practice the code is dead remove the binfmt_flat shared libarary s/libarary/library > support and make maintenance of the code easier. > > [1] https://lkml.kernel.org/r/81788b56-5b15-7308-38c7-c7f2502c4e15@xxxxxxxxxxxxxx > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > --- > > Can the binfmt_flat folks please verify that the shared library support > really isn't used? As mentioned in a different email, it is not supported by the toolchains for riscv. > > Was binfmt_flat being enabled on arm and sh the mistake it looks like? > > arch/arm/configs/lpc18xx_defconfig | 1 - > arch/arm/configs/mps2_defconfig | 1 - > arch/arm/configs/stm32_defconfig | 1 - > arch/arm/configs/vf610m4_defconfig | 1 - > arch/sh/configs/rsk7201_defconfig | 1 - > arch/sh/configs/rsk7203_defconfig | 1 - > arch/sh/configs/se7206_defconfig | 1 - > fs/Kconfig.binfmt | 6 - > fs/binfmt_flat.c | 190 ++++++----------------------- > 9 files changed, 40 insertions(+), 163 deletions(-) > > diff --git a/arch/arm/configs/lpc18xx_defconfig b/arch/arm/configs/lpc18xx_defconfig > index be882ea0eee4..688c9849eec8 100644 > --- a/arch/arm/configs/lpc18xx_defconfig > +++ b/arch/arm/configs/lpc18xx_defconfig > @@ -30,7 +30,6 @@ CONFIG_ARM_APPENDED_DTB=y > # CONFIG_BLK_DEV_BSG is not set > CONFIG_BINFMT_FLAT=y > CONFIG_BINFMT_ZFLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > # CONFIG_COREDUMP is not set > CONFIG_NET=y > CONFIG_PACKET=y > diff --git a/arch/arm/configs/mps2_defconfig b/arch/arm/configs/mps2_defconfig > index 89f4a6ff30bd..c1e98e33a348 100644 > --- a/arch/arm/configs/mps2_defconfig > +++ b/arch/arm/configs/mps2_defconfig > @@ -23,7 +23,6 @@ CONFIG_PREEMPT_VOLUNTARY=y > CONFIG_ZBOOT_ROM_TEXT=0x0 > CONFIG_ZBOOT_ROM_BSS=0x0 > CONFIG_BINFMT_FLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > # CONFIG_COREDUMP is not set > # CONFIG_SUSPEND is not set > CONFIG_NET=y > diff --git a/arch/arm/configs/stm32_defconfig b/arch/arm/configs/stm32_defconfig > index 551db328009d..71d6bfcf4551 100644 > --- a/arch/arm/configs/stm32_defconfig > +++ b/arch/arm/configs/stm32_defconfig > @@ -28,7 +28,6 @@ CONFIG_ZBOOT_ROM_BSS=0x0 > CONFIG_XIP_KERNEL=y > CONFIG_XIP_PHYS_ADDR=0x08008000 > CONFIG_BINFMT_FLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > # CONFIG_COREDUMP is not set > CONFIG_DEVTMPFS=y > CONFIG_DEVTMPFS_MOUNT=y > diff --git a/arch/arm/configs/vf610m4_defconfig b/arch/arm/configs/vf610m4_defconfig > index a89f035c3b01..70fdbfd83484 100644 > --- a/arch/arm/configs/vf610m4_defconfig > +++ b/arch/arm/configs/vf610m4_defconfig > @@ -18,7 +18,6 @@ CONFIG_XIP_KERNEL=y > CONFIG_XIP_PHYS_ADDR=0x0f000080 > CONFIG_BINFMT_FLAT=y > CONFIG_BINFMT_ZFLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > # CONFIG_SUSPEND is not set > # CONFIG_UEVENT_HELPER is not set > # CONFIG_STANDALONE is not set > diff --git a/arch/sh/configs/rsk7201_defconfig b/arch/sh/configs/rsk7201_defconfig > index e41526120be1..619c18699459 100644 > --- a/arch/sh/configs/rsk7201_defconfig > +++ b/arch/sh/configs/rsk7201_defconfig > @@ -25,7 +25,6 @@ CONFIG_CMDLINE_OVERWRITE=y > CONFIG_CMDLINE="console=ttySC0,115200 earlyprintk=serial ignore_loglevel" > CONFIG_BINFMT_FLAT=y > CONFIG_BINFMT_ZFLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > CONFIG_PM=y > CONFIG_CPU_IDLE=y > # CONFIG_STANDALONE is not set > diff --git a/arch/sh/configs/rsk7203_defconfig b/arch/sh/configs/rsk7203_defconfig > index 6af08fa1ddf8..5a54e2b883f0 100644 > --- a/arch/sh/configs/rsk7203_defconfig > +++ b/arch/sh/configs/rsk7203_defconfig > @@ -30,7 +30,6 @@ CONFIG_CMDLINE_OVERWRITE=y > CONFIG_CMDLINE="console=ttySC0,115200 earlyprintk=serial ignore_loglevel" > CONFIG_BINFMT_FLAT=y > CONFIG_BINFMT_ZFLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > CONFIG_PM=y > CONFIG_CPU_IDLE=y > CONFIG_NET=y > diff --git a/arch/sh/configs/se7206_defconfig b/arch/sh/configs/se7206_defconfig > index 601d062250d1..122216123e63 100644 > --- a/arch/sh/configs/se7206_defconfig > +++ b/arch/sh/configs/se7206_defconfig > @@ -40,7 +40,6 @@ CONFIG_CMDLINE_OVERWRITE=y > CONFIG_CMDLINE="console=ttySC3,115200 ignore_loglevel earlyprintk=serial" > CONFIG_BINFMT_FLAT=y > CONFIG_BINFMT_ZFLAT=y > -CONFIG_BINFMT_SHARED_FLAT=y > CONFIG_BINFMT_MISC=y > CONFIG_NET=y > CONFIG_PACKET=y > diff --git a/fs/Kconfig.binfmt b/fs/Kconfig.binfmt > index 21c6332fa785..32dff7ba3dda 100644 > --- a/fs/Kconfig.binfmt > +++ b/fs/Kconfig.binfmt > @@ -142,12 +142,6 @@ config BINFMT_ZFLAT > help > Support FLAT format compressed binaries > > -config BINFMT_SHARED_FLAT > - bool "Enable shared FLAT support" > - depends on BINFMT_FLAT > - help > - Support FLAT shared libraries > - > config HAVE_AOUT > def_bool n > > diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c > index 0ad2c7bbaddd..82e4412a9665 100644 > --- a/fs/binfmt_flat.c > +++ b/fs/binfmt_flat.c > @@ -68,11 +68,7 @@ > #define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */ > #define UNLOADED_LIB 0x7ff000ff /* Placeholder for unused library */ > > -#ifdef CONFIG_BINFMT_SHARED_FLAT > -#define MAX_SHARED_LIBS (4) > -#else > -#define MAX_SHARED_LIBS (1) > -#endif > +#define MAX_SHARED_LIBS (1) > > #ifdef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET > #define DATA_START_OFFSET_WORDS (0) > @@ -92,10 +88,6 @@ struct lib_info { > } lib_list[MAX_SHARED_LIBS]; > }; > > -#ifdef CONFIG_BINFMT_SHARED_FLAT > -static int load_flat_shared_library(int id, struct lib_info *p); > -#endif > - > static int load_flat_binary(struct linux_binprm *); > > static struct linux_binfmt flat_format = { > @@ -307,51 +299,18 @@ static int decompress_exec(struct linux_binprm *bprm, loff_t fpos, char *dst, > /****************************************************************************/ > > static unsigned long > -calc_reloc(unsigned long r, struct lib_info *p, int curid, int internalp) > +calc_reloc(unsigned long r, struct lib_info *p) > { > unsigned long addr; > - int id; > unsigned long start_brk; > unsigned long start_data; > unsigned long text_len; > unsigned long start_code; > > -#ifdef CONFIG_BINFMT_SHARED_FLAT > - if (r == 0) > - id = curid; /* Relocs of 0 are always self referring */ > - else { > - id = (r >> 24) & 0xff; /* Find ID for this reloc */ > - r &= 0x00ffffff; /* Trim ID off here */ > - } > - if (id >= MAX_SHARED_LIBS) { > - pr_err("reference 0x%lx to shared library %d", r, id); > - goto failed; > - } > - if (curid != id) { > - if (internalp) { > - pr_err("reloc address 0x%lx not in same module " > - "(%d != %d)", r, curid, id); > - goto failed; > - } else if (!p->lib_list[id].loaded && > - load_flat_shared_library(id, p) < 0) { > - pr_err("failed to load library %d", id); > - goto failed; > - } > - /* Check versioning information (i.e. time stamps) */ > - if (p->lib_list[id].build_date && p->lib_list[curid].build_date && > - p->lib_list[curid].build_date < p->lib_list[id].build_date) { > - pr_err("library %d is younger than %d", id, curid); > - goto failed; > - } > - } > -#else > - id = 0; > -#endif > - > - start_brk = p->lib_list[id].start_brk; > - start_data = p->lib_list[id].start_data; > - start_code = p->lib_list[id].start_code; > - text_len = p->lib_list[id].text_len; > + start_brk = p->lib_list[0].start_brk; > + start_data = p->lib_list[0].start_data; > + start_code = p->lib_list[0].start_code; > + text_len = p->lib_list[0].text_len; > > if (r > start_brk - start_data + text_len) { > pr_err("reloc outside program 0x%lx (0 - 0x%lx/0x%lx)", > @@ -419,7 +378,7 @@ static void old_reloc(unsigned long rl) > /****************************************************************************/ > > static int load_flat_file(struct linux_binprm *bprm, > - struct lib_info *libinfo, int id, unsigned long *extra_stack) > + struct lib_info *libinfo, unsigned long *extra_stack) > { > struct flat_hdr *hdr; > unsigned long textpos, datapos, realdatastart; > @@ -471,14 +430,6 @@ static int load_flat_file(struct linux_binprm *bprm, > goto err; > } > > - /* Don't allow old format executables to use shared libraries */ > - if (rev == OLD_FLAT_VERSION && id != 0) { > - pr_err("shared libraries are not available before rev 0x%lx\n", > - FLAT_VERSION); > - ret = -ENOEXEC; > - goto err; > - } > - > /* > * fix up the flags for the older format, there were all kinds > * of endian hacks, this only works for the simple cases > @@ -529,15 +480,13 @@ static int load_flat_file(struct linux_binprm *bprm, > } > > /* Flush all traces of the currently running executable */ > - if (id == 0) { > - ret = begin_new_exec(bprm); > - if (ret) > - goto err; > + ret = begin_new_exec(bprm); > + if (ret) > + goto err; > > - /* OK, This is the point of no return */ > - set_personality(PER_LINUX_32BIT); > - setup_new_exec(bprm); > - } > + /* OK, This is the point of no return */ > + set_personality(PER_LINUX_32BIT); > + setup_new_exec(bprm); > > /* > * calculate the extra space we need to map in > @@ -717,42 +666,40 @@ static int load_flat_file(struct linux_binprm *bprm, > text_len -= sizeof(struct flat_hdr); /* the real code len */ > > /* The main program needs a little extra setup in the task structure */ > - if (id == 0) { > - current->mm->start_code = start_code; > - current->mm->end_code = end_code; > - current->mm->start_data = datapos; > - current->mm->end_data = datapos + data_len; > - /* > - * set up the brk stuff, uses any slack left in data/bss/stack > - * allocation. We put the brk after the bss (between the bss > - * and stack) like other platforms. > - * Userspace code relies on the stack pointer starting out at > - * an address right at the end of a page. > - */ > - current->mm->start_brk = datapos + data_len + bss_len; > - current->mm->brk = (current->mm->start_brk + 3) & ~3; > + current->mm->start_code = start_code; > + current->mm->end_code = end_code; > + current->mm->start_data = datapos; > + current->mm->end_data = datapos + data_len; > + /* > + * set up the brk stuff, uses any slack left in data/bss/stack > + * allocation. We put the brk after the bss (between the bss > + * and stack) like other platforms. > + * Userspace code relies on the stack pointer starting out at > + * an address right at the end of a page. > + */ > + current->mm->start_brk = datapos + data_len + bss_len; > + current->mm->brk = (current->mm->start_brk + 3) & ~3; > #ifndef CONFIG_MMU > - current->mm->context.end_brk = memp + memp_size - stack_len; > + current->mm->context.end_brk = memp + memp_size - stack_len; > #endif > - } > > if (flags & FLAT_FLAG_KTRACE) { > pr_info("Mapping is %lx, Entry point is %x, data_start is %x\n", > textpos, 0x00ffffff&ntohl(hdr->entry), ntohl(hdr->data_start)); > pr_info("%s %s: TEXT=%lx-%lx DATA=%lx-%lx BSS=%lx-%lx\n", > - id ? "Lib" : "Load", bprm->filename, > + "Load", bprm->filename, > start_code, end_code, datapos, datapos + data_len, > datapos + data_len, (datapos + data_len + bss_len + 3) & ~3); > } > > /* Store the current module values into the global library structure */ > - libinfo->lib_list[id].start_code = start_code; > - libinfo->lib_list[id].start_data = datapos; > - libinfo->lib_list[id].start_brk = datapos + data_len + bss_len; > - libinfo->lib_list[id].text_len = text_len; > - libinfo->lib_list[id].loaded = 1; > - libinfo->lib_list[id].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; > - libinfo->lib_list[id].build_date = ntohl(hdr->build_date); > + libinfo->lib_list[0].start_code = start_code; > + libinfo->lib_list[0].start_data = datapos; > + libinfo->lib_list[0].start_brk = datapos + data_len + bss_len; > + libinfo->lib_list[0].text_len = text_len; > + libinfo->lib_list[0].loaded = 1; > + libinfo->lib_list[0].entry = (0x00ffffff & ntohl(hdr->entry)) + textpos; > + libinfo->lib_list[0].build_date = ntohl(hdr->build_date); > > /* > * We just load the allocations into some temporary memory to > @@ -774,7 +721,7 @@ static int load_flat_file(struct linux_binprm *bprm, > if (rp_val == 0xffffffff) > break; > if (rp_val) { > - addr = calc_reloc(rp_val, libinfo, id, 0); > + addr = calc_reloc(rp_val, libinfo); > if (addr == RELOC_FAILED) { > ret = -ENOEXEC; > goto err; > @@ -810,7 +757,7 @@ static int load_flat_file(struct linux_binprm *bprm, > return -EFAULT; > relval = ntohl(tmp); > addr = flat_get_relocate_addr(relval); > - rp = (u32 __user *)calc_reloc(addr, libinfo, id, 1); > + rp = (u32 __user *)calc_reloc(addr, libinfo); > if (rp == (u32 __user *)RELOC_FAILED) { > ret = -ENOEXEC; > goto err; > @@ -833,7 +780,7 @@ static int load_flat_file(struct linux_binprm *bprm, > */ > addr = ntohl((__force __be32)addr); > } > - addr = calc_reloc(addr, libinfo, id, 0); > + addr = calc_reloc(addr, libinfo); > if (addr == RELOC_FAILED) { > ret = -ENOEXEC; > goto err; > @@ -861,7 +808,7 @@ static int load_flat_file(struct linux_binprm *bprm, > /* zero the BSS, BRK and stack areas */ > if (clear_user((void __user *)(datapos + data_len), bss_len + > (memp + memp_size - stack_len - /* end brk */ > - libinfo->lib_list[id].start_brk) + /* start brk */ > + libinfo->lib_list[0].start_brk) + /* start brk */ > stack_len)) > return -EFAULT; > > @@ -871,49 +818,6 @@ static int load_flat_file(struct linux_binprm *bprm, > } > > > -/****************************************************************************/ > -#ifdef CONFIG_BINFMT_SHARED_FLAT > - > -/* > - * Load a shared library into memory. The library gets its own data > - * segment (including bss) but not argv/argc/environ. > - */ > - > -static int load_flat_shared_library(int id, struct lib_info *libs) > -{ > - /* > - * This is a fake bprm struct; only the members "buf", "file" and > - * "filename" are actually used. > - */ > - struct linux_binprm bprm; > - int res; > - char buf[16]; > - loff_t pos = 0; > - > - memset(&bprm, 0, sizeof(bprm)); > - > - /* Create the file name */ > - sprintf(buf, "/lib/lib%d.so", id); > - > - /* Open the file up */ > - bprm.filename = buf; > - bprm.file = open_exec(bprm.filename); > - res = PTR_ERR(bprm.file); > - if (IS_ERR(bprm.file)) > - return res; > - > - res = kernel_read(bprm.file, bprm.buf, BINPRM_BUF_SIZE, &pos); > - > - if (res >= 0) > - res = load_flat_file(&bprm, libs, id, NULL); > - > - allow_write_access(bprm.file); > - fput(bprm.file); > - > - return res; > -} > - > -#endif /* CONFIG_BINFMT_SHARED_FLAT */ > /****************************************************************************/ > > /* > @@ -946,7 +850,7 @@ static int load_flat_binary(struct linux_binprm *bprm) > stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */ > stack_len = ALIGN(stack_len, FLAT_STACK_ALIGN); > > - res = load_flat_file(bprm, &libinfo, 0, &stack_len); > + res = load_flat_file(bprm, &libinfo, &stack_len); > if (res < 0) > return res; > > @@ -991,20 +895,6 @@ static int load_flat_binary(struct linux_binprm *bprm) > */ > start_addr = libinfo.lib_list[0].entry; > > -#ifdef CONFIG_BINFMT_SHARED_FLAT > - for (i = MAX_SHARED_LIBS-1; i > 0; i--) { > - if (libinfo.lib_list[i].loaded) { > - /* Push previos first to call address */ > - unsigned long __user *sp; > - current->mm->start_stack -= sizeof(unsigned long); > - sp = (unsigned long __user *)current->mm->start_stack; > - if (put_user(start_addr, sp)) > - return -EFAULT; > - start_addr = libinfo.lib_list[i].entry; > - } > - } > -#endif > - > #ifdef FLAT_PLAT_INIT > FLAT_PLAT_INIT(regs); > #endif Apart from the typos mentioned above, looks OK to me. Reviewed-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx> -- Damien Le Moal Western Digital Research
