On Tue, Feb 11, 2020 at 01:09:41PM -0700, Simon Glass wrote:
> Allow enabling ASSUME_VALID_INPUT to disable sanity checks on the device
> tree and the parameters to libfdt. This assumption covers that cases where
> the problem could be with either.
>
> Signed-off-by: Simon Glass <sjg@xxxxxxxxxxxx>
> ---
>
> Changes in v6:
> - Don't add VALID_INPUT to fdt_get_property_namelen_()
> - Drop assumption in fdt_nodename_eq_()
>
> Changes in v5:
> - Include just VALID_INPUT checks in this patch
>
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
>
> libfdt/fdt.c | 14 ++++++++----
> libfdt/fdt_ro.c | 61 +++++++++++++++++++++++++++++++++----------------
> 2 files changed, 50 insertions(+), 25 deletions(-)
>
> diff --git a/libfdt/fdt.c b/libfdt/fdt.c
> index d4daf60..f6600ff 100644
> --- a/libfdt/fdt.c
> +++ b/libfdt/fdt.c
> @@ -129,10 +129,11 @@ const void *fdt_offset_ptr(const void *fdt, int offset, unsigned int len)
> {
> unsigned absoffset = offset + fdt_off_dt_struct(fdt);
>
> - if ((absoffset < offset)
> - || ((absoffset + len) < absoffset)
> - || (absoffset + len) > fdt_totalsize(fdt))
> - return NULL;
> + if (!can_assume(VALID_INPUT))
> + if ((absoffset < offset)
> + || ((absoffset + len) < absoffset)
> + || (absoffset + len) > fdt_totalsize(fdt))
> + return NULL;
>
> if (fdt_version(fdt) >= 0x11)
> if (((offset + len) < offset)
> @@ -188,7 +189,8 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
> return FDT_END;
> }
>
> - if (!fdt_offset_ptr(fdt, startoffset, offset - startoffset))
> + if (!can_assume(VALID_INPUT) &&
> + !fdt_offset_ptr(fdt, startoffset, offset - startoffset))
If fdt_offset_ptr() has a can_assume() inside, can't some of these
calls to it avoid the can_assume()?
> return FDT_END; /* premature end */
>
> *nextoffset = FDT_TAGALIGN(offset);
> @@ -197,6 +199,8 @@ uint32_t fdt_next_tag(const void *fdt, int startoffset, int *nextoffset)
>
> int fdt_check_node_offset_(const void *fdt, int offset)
> {
> + if (can_assume(VALID_INPUT))
> + return offset;
> if ((offset < 0) || (offset % FDT_TAGSIZE)
> || (fdt_next_tag(fdt, offset, &offset) != FDT_BEGIN_NODE))
> return -FDT_ERR_BADOFFSET;
> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
> index 4c26fbe..9c32559 100644
> --- a/libfdt/fdt_ro.c
> +++ b/libfdt/fdt_ro.c
> @@ -33,17 +33,26 @@ static int fdt_nodename_eq_(const void *fdt, int offset,
>
> const char *fdt_get_string(const void *fdt, int stroffset, int *lenp)
> {
> - int32_t totalsize = fdt_ro_probe_(fdt);
> - uint32_t absoffset = stroffset + fdt_off_dt_strings(fdt);
> + int32_t totalsize;
> + uint32_t absoffset;
> size_t len;
> int err;
> const char *s, *n;
>
> + if (can_assume(VALID_INPUT)) {
> + s = (const char *)fdt + fdt_off_dt_strings(fdt) + stroffset;
> +
> + if (lenp)
> + *lenp = strlen(s);
> + return s;
> + }
> + totalsize = fdt_ro_probe_(fdt);
> err = totalsize;
> if (totalsize < 0)
> goto fail;
>
> err = -FDT_ERR_BADOFFSET;
> + absoffset = stroffset + fdt_off_dt_strings(fdt);
> if (absoffset >= totalsize)
> goto fail;
> len = totalsize - absoffset;
> @@ -151,10 +160,13 @@ static const struct fdt_reserve_entry *fdt_mem_rsv(const void *fdt, int n)
> int offset = n * sizeof(struct fdt_reserve_entry);
> int absoffset = fdt_off_mem_rsvmap(fdt) + offset;
>
> - if (absoffset < fdt_off_mem_rsvmap(fdt))
> - return NULL;
> - if (absoffset > fdt_totalsize(fdt) - sizeof(struct fdt_reserve_entry))
> - return NULL;
> + if (!can_assume(VALID_INPUT)) {
> + if (absoffset < fdt_off_mem_rsvmap(fdt))
> + return NULL;
> + if (absoffset > fdt_totalsize(fdt) -
> + sizeof(struct fdt_reserve_entry))
> + return NULL;
> + }
> return fdt_mem_rsv_(fdt, n);
> }
>
> @@ -164,7 +176,7 @@ int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
>
> FDT_RO_PROBE(fdt);
> re = fdt_mem_rsv(fdt, n);
> - if (!re)
> + if (!can_assume(VALID_INPUT) && !re)
> return -FDT_ERR_BADOFFSET;
>
> *address = fdt64_ld(&re->address);
> @@ -346,7 +358,8 @@ static const struct fdt_property *fdt_get_property_by_offset_(const void *fdt,
> int err;
> const struct fdt_property *prop;
>
> - if ((err = fdt_check_prop_offset_(fdt, offset)) < 0) {
> + if (!can_assume(VALID_INPUT) &&
> + (err = fdt_check_prop_offset_(fdt, offset)) < 0) {
> if (lenp)
> *lenp = err;
> return NULL;
> @@ -462,14 +475,19 @@ const void *fdt_getprop_by_offset(const void *fdt, int offset,
> if (namep) {
> const char *name;
> int namelen;
> - name = fdt_get_string(fdt, fdt32_ld(&prop->nameoff),
> - &namelen);
> - if (!name) {
> - if (lenp)
> - *lenp = namelen;
> - return NULL;
> +
> + if (!can_assume(VALID_INPUT)) {
> + name = fdt_get_string(fdt, fdt32_ld(&prop->nameoff),
> + &namelen);
> + if (!name) {
> + if (lenp)
> + *lenp = namelen;
> + return NULL;
> + }
> + *namep = name;
> + } else {
> + *namep = fdt_string(fdt, fdt32_ld(&prop->nameoff));
> }
> - *namep = name;
> }
>
> /* Handle realignment */
> @@ -599,10 +617,12 @@ int fdt_supernode_atdepth_offset(const void *fdt, int nodeoffset,
> }
> }
>
> - if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
> - return -FDT_ERR_BADOFFSET;
> - else if (offset == -FDT_ERR_BADOFFSET)
> - return -FDT_ERR_BADSTRUCTURE;
> + if (!can_assume(VALID_INPUT)) {
> + if ((offset == -FDT_ERR_NOTFOUND) || (offset >= 0))
> + return -FDT_ERR_BADOFFSET;
> + else if (offset == -FDT_ERR_BADOFFSET)
> + return -FDT_ERR_BADSTRUCTURE;
> + }
>
> return offset; /* error from fdt_next_node() */
> }
> @@ -614,7 +634,8 @@ int fdt_node_depth(const void *fdt, int nodeoffset)
>
> err = fdt_supernode_atdepth_offset(fdt, nodeoffset, 0, &nodedepth);
> if (err)
> - return (err < 0) ? err : -FDT_ERR_INTERNAL;
> + return (can_assume(VALID_INPUT) || err < 0) ? err :
> + -FDT_ERR_INTERNAL;
> return nodedepth;
> }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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