Adding Kees into CC because it is security related. Adding Andrew into CC because he usually takes patches for hexdump.
On Wed 2021-01-06 15:35:47, Timur Tabi wrote: > Hashed addresses are useless in hexdumps unless you're comparing > with other hashed addresses, which is unlikely. However, there's > no need to break existing code, so introduce a new prefix type > that prints unhashed addresses. > > Signed-off-by: Timur Tabi <[email protected]> > Cc: Roman Fietze <[email protected]> I agree that there should be way to print the real address. And it is sane to add a new mode so that the current users stay hashed. Reviewed-by: Petr Mladek <[email protected]> > --- > include/linux/printk.h | 3 ++- > lib/hexdump.c | 9 +++++++-- > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/include/linux/printk.h b/include/linux/printk.h > index fe7eb2351610..5d833bad785c 100644 > --- a/include/linux/printk.h > +++ b/include/linux/printk.h > @@ -567,7 +567,8 @@ extern const struct file_operations kmsg_fops; > enum { > DUMP_PREFIX_NONE, > DUMP_PREFIX_ADDRESS, > - DUMP_PREFIX_OFFSET > + DUMP_PREFIX_OFFSET, > + DUMP_PREFIX_UNHASHED, > }; > extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, > int groupsize, char *linebuf, size_t linebuflen, > diff --git a/lib/hexdump.c b/lib/hexdump.c > index 9301578f98e8..b5acfc4168a8 100644 > --- a/lib/hexdump.c > +++ b/lib/hexdump.c > @@ -211,8 +211,9 @@ EXPORT_SYMBOL(hex_dump_to_buffer); > * @level: kernel log level (e.g. KERN_DEBUG) > * @prefix_str: string to prefix each line with; > * caller supplies trailing spaces for alignment if desired > - * @prefix_type: controls whether prefix of an offset, address, or none > - * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE) > + * @prefix_type: controls whether prefix of an offset, hashed address, > + * unhashed address, or none is printed (%DUMP_PREFIX_OFFSET, > + * %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_UNHASHED, %DUMP_PREFIX_NONE) > * @rowsize: number of bytes to print per line; must be 16 or 32 > * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1) > * @buf: data blob to dump > @@ -256,6 +257,10 @@ void print_hex_dump(const char *level, const char > *prefix_str, int prefix_type, > linebuf, sizeof(linebuf), ascii); > > switch (prefix_type) { > + case DUMP_PREFIX_UNHASHED: > + printk("%s%s%px: %s\n", > + level, prefix_str, ptr + i, linebuf); > + break; > case DUMP_PREFIX_ADDRESS: > printk("%s%s%p: %s\n", > level, prefix_str, ptr + i, linebuf); > -- > 2.25.1
