coredump, vmcore: Set p_align to 4 for PT_NOTE

JIRA: https://issues.redhat.com/browse/RHEL-32199

Upstream Status: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

Conflict: There's fuzz in fs/binfmt_elf.c which need be handled
          manually.

commit 60592fb
Author: Fangrui Song <maskray@google.com>
Date:   Fri May 12 02:25:28 2023 +0000

    coredump, vmcore: Set p_align to 4 for PT_NOTE

    Tools like readelf/llvm-readelf use p_align to parse a PT_NOTE program
    header as an array of 4-byte entries or 8-byte entries. Currently, there
    are workarounds[1] in place for Linux to treat p_align==0 as 4. However,
    it would be more appropriate to set the correct alignment so that tools
    do not have to rely on guesswork. FreeBSD coredumps set p_align to 4 as
    well.

    [1]: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=82ed9683ec099d8205dc499ac84febc975235af6
    [2]: https://reviews.llvm.org/D150022

    Signed-off-by: Fangrui Song <maskray@google.com>
    Signed-off-by: Kees Cook <keescook@chromium.org>
    Link: https://lore.kernel.org/r/20230512022528.3430327-1-maskray@google.com

Signed-off-by: Baoquan He <bhe@redhat.com>

Author: Baoquan He

fs/binfmt_elf.c

@@ -1482,7 +1482,7 @@ static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
 	phdr->p_filesz = sz;
 	phdr->p_memsz = 0;
 	phdr->p_flags = 0;
-	phdr->p_align = 0;
+	phdr->p_align = 4;
 }
 
 static void fill_note(struct memelfnote *note, const char *name, int type, 

fs/binfmt_elf_fdpic.c

@@ -1268,7 +1268,7 @@ static inline void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offs
 	phdr->p_filesz = sz;
 	phdr->p_memsz = 0;
 	phdr->p_flags = 0;
-	phdr->p_align = 0;
+	phdr->p_align = 4;
 	return;
 }
 

fs/proc/vmcore.c

@@ -879,7 +879,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 	phdr.p_vaddr   = phdr.p_paddr = 0;
 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
-	phdr.p_align   = 0;
+	phdr.p_align   = 4;
 
 	/* Add merged PT_NOTE program header*/
 	tmp = elfptr + sizeof(Elf64_Ehdr);
@@ -1070,7 +1070,7 @@ static int __init merge_note_headers_elf32(char *elfptr, size_t *elfsz,
 	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 	phdr.p_vaddr   = phdr.p_paddr = 0;
 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
-	phdr.p_align   = 0;
+	phdr.p_align   = 4;
 
 	/* Add merged PT_NOTE program header*/
 	tmp = elfptr + sizeof(Elf32_Ehdr);