On Thu 11-01-18 16:47:35, Dan Williams wrote: > Static analysis reports that 'eahd->appAttrLocation' and > 'eahd->impAttrLocation' may be a user controlled values that are used as > data dependencies for calculating source and destination buffers for > memmove operations. In order to avoid potential leaks of kernel memory > values, block speculative execution of the instruction stream that could > issue further reads based on invalid 'aal' or 'ial' values. > > Based on an original patch by Elena Reshetova. > > Cc: Jan Kara <jack@xxxxxxxx> > Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> Dan, I've already emailed to you [1] why I don't think this patch is needed at all. Do you disagree or did my email just get lost? [1] https://marc.info/?l=linux-arch&m=151540683024125&w=2 Honza > --- > fs/udf/misc.c | 40 ++++++++++++++++++++++------------------ > 1 file changed, 22 insertions(+), 18 deletions(-) > > diff --git a/fs/udf/misc.c b/fs/udf/misc.c > index 401e64cde1be..693e24699928 100644 > --- a/fs/udf/misc.c > +++ b/fs/udf/misc.c > @@ -22,6 +22,7 @@ > #include "udfdecl.h" > > #include <linux/fs.h> > +#include <linux/nospec.h> > #include <linux/string.h> > #include <linux/crc-itu-t.h> > > @@ -51,6 +52,8 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size, > int offset; > uint16_t crclen; > struct udf_inode_info *iinfo = UDF_I(inode); > + uint8_t *ea_dst, *ea_src; > + uint32_t aal, ial; > > ea = iinfo->i_ext.i_data; > if (iinfo->i_lenEAttr) { > @@ -100,33 +103,34 @@ struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size, > > offset = iinfo->i_lenEAttr; > if (type < 2048) { > - if (le32_to_cpu(eahd->appAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t aal = > - le32_to_cpu(eahd->appAttrLocation); > - memmove(&ea[offset - aal + size], > - &ea[aal], offset - aal); > + aal = le32_to_cpu(eahd->appAttrLocation); > + ea_dst = array_ptr(ea, offset - aal + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - aal); > offset -= aal; > eahd->appAttrLocation = > cpu_to_le32(aal + size); > } > - if (le32_to_cpu(eahd->impAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t ial = > - le32_to_cpu(eahd->impAttrLocation); > - memmove(&ea[offset - ial + size], > - &ea[ial], offset - ial); > + > + ial = le32_to_cpu(eahd->impAttrLocation); > + ea_dst = array_ptr(ea, offset - ial + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, ial, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - ial); > offset -= ial; > eahd->impAttrLocation = > cpu_to_le32(ial + size); > } > } else if (type < 65536) { > - if (le32_to_cpu(eahd->appAttrLocation) < > - iinfo->i_lenEAttr) { > - uint32_t aal = > - le32_to_cpu(eahd->appAttrLocation); > - memmove(&ea[offset - aal + size], > - &ea[aal], offset - aal); > + aal = le32_to_cpu(eahd->appAttrLocation); > + ea_dst = array_ptr(ea, offset - aal + size, > + iinfo->i_lenEAttr); > + ea_src = array_ptr(ea, aal, iinfo->i_lenEAttr); > + if (ea_dst && ea_src) { > + memmove(ea_dst, ea_src, offset - aal); > offset -= aal; > eahd->appAttrLocation = > cpu_to_le32(aal + size); > > -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
