Commit 59ef28b1f14899b10d6b2682c7057ca00a9a3f47
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module: fix out-by-one error in kallsyms
Masaki found and patched a kallsyms issue: the last symbol in a module's symtab wasn't transferred. This is because we manually copy the zero'th entry (which is always empty) then copy the rest in a loop starting at 1, though from src[0]. His fix was minimal, I prefer to rewrite the loops in more standard form. There are two loops: one to get the size, and one to copy. Make these identical: always count entry 0 and any defined symbol in an allocated non-init section. This bug exists since the following commit was introduced. module: reduce symbol table for loaded modules (v2) commit: 4a4962263f07d14660849ec134ee42b63e95ea9a LKML: http://lkml.org/lkml/2012/10/24/27 Reported-by: Masaki Kimura <masaki.kimura.kz@hitachi.com> Cc: stable@kernel.org
Showing 1 changed file with 16 additions and 11 deletions Side-by-side Diff
kernel/module.c
| ... | ... | @@ -2293,12 +2293,17 @@ |
| 2293 | 2293 | src = (void *)info->hdr + symsect->sh_offset; |
| 2294 | 2294 | nsrc = symsect->sh_size / sizeof(*src); |
| 2295 | 2295 | |
| 2296 | + /* strtab always starts with a nul, so offset 0 is the empty string. */ | |
| 2297 | + strtab_size = 1; | |
| 2298 | + | |
| 2296 | 2299 | /* Compute total space required for the core symbols' strtab. */ |
| 2297 | - for (ndst = i = strtab_size = 1; i < nsrc; ++i, ++src) | |
| 2298 | - if (is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) { | |
| 2299 | - strtab_size += strlen(&info->strtab[src->st_name]) + 1; | |
| 2300 | + for (ndst = i = 0; i < nsrc; i++) { | |
| 2301 | + if (i == 0 || | |
| 2302 | + is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) { | |
| 2303 | + strtab_size += strlen(&info->strtab[src[i].st_name])+1; | |
| 2300 | 2304 | ndst++; |
| 2301 | 2305 | } |
| 2306 | + } | |
| 2302 | 2307 | |
| 2303 | 2308 | /* Append room for core symbols at end of core part. */ |
| 2304 | 2309 | info->symoffs = ALIGN(mod->core_size, symsect->sh_addralign ?: 1); |
| 2305 | 2310 | |
| ... | ... | @@ -2332,15 +2337,15 @@ |
| 2332 | 2337 | mod->core_symtab = dst = mod->module_core + info->symoffs; |
| 2333 | 2338 | mod->core_strtab = s = mod->module_core + info->stroffs; |
| 2334 | 2339 | src = mod->symtab; |
| 2335 | - *dst = *src; | |
| 2336 | 2340 | *s++ = 0; |
| 2337 | - for (ndst = i = 1; i < mod->num_symtab; ++i, ++src) { | |
| 2338 | - if (!is_core_symbol(src, info->sechdrs, info->hdr->e_shnum)) | |
| 2339 | - continue; | |
| 2340 | - | |
| 2341 | - dst[ndst] = *src; | |
| 2342 | - dst[ndst++].st_name = s - mod->core_strtab; | |
| 2343 | - s += strlcpy(s, &mod->strtab[src->st_name], KSYM_NAME_LEN) + 1; | |
| 2341 | + for (ndst = i = 0; i < mod->num_symtab; i++) { | |
| 2342 | + if (i == 0 || | |
| 2343 | + is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum)) { | |
| 2344 | + dst[ndst] = src[i]; | |
| 2345 | + dst[ndst++].st_name = s - mod->core_strtab; | |
| 2346 | + s += strlcpy(s, &mod->strtab[src[i].st_name], | |
| 2347 | + KSYM_NAME_LEN) + 1; | |
| 2348 | + } | |
| 2344 | 2349 | } |
| 2345 | 2350 | mod->core_num_syms = ndst; |
| 2346 | 2351 | } |