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[10/20] module: Manual replacement of the deprecated strlcpy() with return values

Message ID 20210222151231.22572-11-romain.perier@gmail.com (mailing list archive)
State New, archived
Headers show
Series Manual replacement of all strlcpy in favor of strscpy | expand

Commit Message

Romain Perier Feb. 22, 2021, 3:12 p.m. UTC
The strlcpy() reads the entire source buffer first, it is dangerous if
the source buffer lenght is unbounded or possibility non NULL-terminated.
It can lead to linear read overflows, crashes, etc...

As recommended in the deprecated interfaces [1], it should be replaced
by strscpy.

This commit replaces all calls to strlcpy that handle the return values
by the corresponding strscpy calls with new handling of the return
values (as it is quite different between the two functions).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy

Signed-off-by: Romain Perier <romain.perier@gmail.com>
 kernel/module.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
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diff --git a/kernel/module.c b/kernel/module.c
index 4bf30e4b3eaa..46aad8e92a81 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2814,6 +2814,7 @@  static void add_kallsyms(struct module *mod, const struct load_info *info)
 	Elf_Sym *dst;
 	char *s;
 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
+	ssize_t len;
 	/* Set up to point into init section. */
 	mod->kallsyms = mod->init_layout.base + info->mod_kallsyms_init_off;
@@ -2841,8 +2842,9 @@  static void add_kallsyms(struct module *mod, const struct load_info *info)
 			dst[ndst] = src[i];
 			dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
-			s += strlcpy(s, &mod->kallsyms->strtab[src[i].st_name],
+			len = strscpy(s, &mod->kallsyms->strtab[src[i].st_name],
 				     KSYM_NAME_LEN) + 1;
+			s += (len != -E2BIG) ? len : 0;
 	mod->core_kallsyms.num_symtab = ndst;