cecb262571
Add the board/riscv/nommu directory to add a Linux kernel patch used for all RISC-V NOMMU builds (QEMU and Canaan Kendryte K210 SoC based boards). The patch is upstream and will be part of the upcoming 5.19 release. Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
111 lines
3.5 KiB
Diff
111 lines
3.5 KiB
Diff
From 6045ab5fea4c849153ebeb0acb532da5f29d69c4 Mon Sep 17 00:00:00 2001
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From: Niklas Cassel <niklas.cassel@wdc.com>
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Date: Thu, 14 Apr 2022 11:10:18 +0200
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Subject: binfmt_flat: do not stop relocating GOT entries prematurely on riscv
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Upstream commit 6045ab5fea4c849153ebeb0acb532da5f29d69c4.
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bFLT binaries are usually created using elf2flt.
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The linker script used by elf2flt has defined the .data section like the
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following for the last 19 years:
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.data : {
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_sdata = . ;
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__data_start = . ;
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data_start = . ;
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*(.got.plt)
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*(.got)
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FILL(0) ;
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. = ALIGN(0x20) ;
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LONG(-1)
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. = ALIGN(0x20) ;
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...
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}
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It places the .got.plt input section before the .got input section.
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The same is true for the default linker script (ld --verbose) on most
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architectures except x86/x86-64.
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The binfmt_flat loader should relocate all GOT entries until it encounters
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a -1 (the LONG(-1) in the linker script).
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The problem is that the .got.plt input section starts with a GOTPLT header
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(which has size 16 bytes on elf64-riscv and 8 bytes on elf32-riscv), where
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the first word is set to -1. See the binutils implementation for riscv [1].
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This causes the binfmt_flat loader to stop relocating GOT entries
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prematurely and thus causes the application to crash when running.
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Fix this by skipping the whole GOTPLT header, since the whole GOTPLT header
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is reserved for the dynamic linker.
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The GOTPLT header will only be skipped for bFLT binaries with flag
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FLAT_FLAG_GOTPIC set. This flag is unconditionally set by elf2flt if the
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supplied ELF binary has the symbol _GLOBAL_OFFSET_TABLE_ defined.
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ELF binaries without a .got input section should thus remain unaffected.
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Tested on RISC-V Canaan Kendryte K210 and RISC-V QEMU nommu_virt_defconfig.
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[1] https://sourceware.org/git/?p=binutils-gdb.git;a=blob;f=bfd/elfnn-riscv.c;hb=binutils-2_38#l3275
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Cc: <stable@vger.kernel.org>
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Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
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Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
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Link: https://lore.kernel.org/r/20220414091018.896737-1-niklas.cassel@wdc.com
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Fixed-by: kernel test robot <lkp@intel.com>
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Link: https://lore.kernel.org/lkml/202204182333.OIUOotK8-lkp@intel.com
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Signed-off-by: Kees Cook <keescook@chromium.org>
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---
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fs/binfmt_flat.c | 27 ++++++++++++++++++++++++++-
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1 file changed, 26 insertions(+), 1 deletion(-)
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diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
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index 6268981500112..dca0b6875f9c3 100644
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--- a/fs/binfmt_flat.c
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+++ b/fs/binfmt_flat.c
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@@ -440,6 +440,30 @@ static void old_reloc(unsigned long rl)
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/****************************************************************************/
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+static inline u32 __user *skip_got_header(u32 __user *rp)
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+{
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+ if (IS_ENABLED(CONFIG_RISCV)) {
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+ /*
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+ * RISC-V has a 16 byte GOT PLT header for elf64-riscv
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+ * and 8 byte GOT PLT header for elf32-riscv.
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+ * Skip the whole GOT PLT header, since it is reserved
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+ * for the dynamic linker (ld.so).
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+ */
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+ u32 rp_val0, rp_val1;
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+
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+ if (get_user(rp_val0, rp))
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+ return rp;
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+ if (get_user(rp_val1, rp + 1))
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+ return rp;
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+
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+ if (rp_val0 == 0xffffffff && rp_val1 == 0xffffffff)
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+ rp += 4;
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+ else if (rp_val0 == 0xffffffff)
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+ rp += 2;
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+ }
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+ return rp;
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+}
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+
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static int load_flat_file(struct linux_binprm *bprm,
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struct lib_info *libinfo, int id, unsigned long *extra_stack)
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{
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@@ -789,7 +813,8 @@ static int load_flat_file(struct linux_binprm *bprm,
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* image.
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*/
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if (flags & FLAT_FLAG_GOTPIC) {
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- for (rp = (u32 __user *)datapos; ; rp++) {
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+ rp = skip_got_header((u32 __user *) datapos);
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+ for (; ; rp++) {
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u32 addr, rp_val;
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if (get_user(rp_val, rp))
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return -EFAULT;
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--
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cgit
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