libkmod-module: mangle the section header, not the section

When we are told to remove the "__versions" section we were mangling
that section instead of tweaking the SHF_ALLOC flag in its header.

diff --git a/libkmod/libkmod-elf.c b/libkmod/libkmod-elf.c
index dc5a83e55cca6f7522fb5cb0a0176396d7257843..ef6bd2a112c9aea0d7af5244f5701bd11518c89c 100644 (file)
--- a/libkmod/libkmod-elf.c
+++ b/libkmod/libkmod-elf.c
@@ -375,6 +375,31 @@ const void *kmod_elf_get_memory(const struct kmod_elf *elf)
        return elf->memory;
 }
 
+static int elf_find_section(const struct kmod_elf *elf, const char *section)
+{
+       uint64_t nameslen;
+       const char *names = elf_get_strings_section(elf, &nameslen);
+       uint16_t i;
+
+       for (i = 1; i < elf->header.section.count; i++) {
+               uint64_t off, size;
+               uint32_t nameoff;
+               const char *n;
+               int err = elf_get_section_info(elf, i, &off, &size, &nameoff);
+               if (err < 0)
+                       continue;
+               if (nameoff >= nameslen)
+                       continue;
+               n = names + nameoff;
+               if (!streq(section, n))
+                       continue;
+
+               return i;
+       }
+
+       return -ENOENT;
+}
+
 int kmod_elf_get_section(const struct kmod_elf *elf, const char *section, const void **buf, uint64_t *buf_size)
 {
        uint64_t nameslen;
@@ -550,26 +575,29 @@ int kmod_elf_get_modversions(const struct kmod_elf *elf, struct kmod_modversion
 
 int kmod_elf_strip_section(struct kmod_elf *elf, const char *section)
 {
-       uint64_t size, off;
+       uint64_t off, size;
        const void *buf;
-       int err = kmod_elf_get_section(elf, section, &buf, &size);
-       if (err < 0)
-               return err;
+       int idx = elf_find_section(elf, section);
+       uint64_t val;
 
+       if (idx < 0)
+               return idx;
+
+       buf = elf_get_section_header(elf, idx);
        off = (const uint8_t *)buf - elf->memory;
 
-#define WRITEV(field, value)                   \
-       elf_set_uint(elf, off + offsetof(typeof(*hdr), field), sizeof(hdr->field), value)
        if (elf->class & KMOD_ELF_32) {
-               const Elf32_Shdr *hdr _unused_ = buf;
-               uint32_t val = ~(uint32_t)SHF_ALLOC;
-               return WRITEV(sh_flags, val);
+               off += offsetof(Elf32_Shdr, sh_flags);
+               size = sizeof(((Elf32_Shdr *)buf)->sh_flags);
        } else {
-               const Elf64_Shdr *hdr _unused_ = buf;
-               uint64_t val = ~(uint64_t)SHF_ALLOC;
-               return WRITEV(sh_flags, val);
+               off += offsetof(Elf64_Shdr, sh_flags);
+               size = sizeof(((Elf64_Shdr *)buf)->sh_flags);
        }
-#undef WRITEV
+
+       val = elf_get_uint(elf, off, size);
+       val &= ~(uint64_t)SHF_ALLOC;
+
+       return elf_set_uint(elf, off, size, val);
 }
 
 int kmod_elf_strip_vermagic(struct kmod_elf *elf)