From eb27f9b7bf9c1dc902d9545eecf805831bd4e46c Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:18:12 -0800 Subject: [PATCH 1/8] CVE-2015-7560: s3: smbd: Add refuse_symlink() function that can be used to prevent operations on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 26b6523..7f47579 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -51,6 +51,34 @@ static char *store_file_unix_basic_info2(connection_struct *conn, files_struct *fsp, const SMB_STRUCT_STAT *psbuf); +/**************************************************************************** + Check if an open file handle or pathname is a symlink. +****************************************************************************/ + +static NTSTATUS refuse_symlink(connection_struct *conn, + const files_struct *fsp, + const char *name) +{ + SMB_STRUCT_STAT sbuf; + const SMB_STRUCT_STAT *pst = NULL; + + if (fsp) { + pst = &fsp->fsp_name->st; + } else { + int ret = vfs_stat_smb_fname(conn, + name, + &sbuf); + if (ret == -1) { + return map_nt_error_from_unix(errno); + } + pst = &sbuf; + } + if (S_ISLNK(pst->st_ex_mode)) { + return NT_STATUS_ACCESS_DENIED; + } + return NT_STATUS_OK; +} + /******************************************************************** Roundup a value to the nearest allocation roundup size boundary. Only do this for Windows clients. -- 2.5.0 From f5b1bcc51e18bc85f376701bb4ae6894d97addfd Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 10:38:28 -0800 Subject: [PATCH 2/8] CVE-2015-7560: s3: smbd: Refuse to get an ACL from a POSIX file handle on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/nttrans.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/source3/smbd/nttrans.c b/source3/smbd/nttrans.c index 4c145e0..7255600 100644 --- a/source3/smbd/nttrans.c +++ b/source3/smbd/nttrans.c @@ -1925,6 +1925,12 @@ NTSTATUS smbd_do_query_security_desc(connection_struct *conn, return NT_STATUS_ACCESS_DENIED; } + if (S_ISLNK(fsp->fsp_name->st.st_ex_mode)) { + DEBUG(10, ("ACL get on symlink %s denied.\n", + fsp_str_dbg(fsp))); + return NT_STATUS_ACCESS_DENIED; + } + if (security_info_wanted & (SECINFO_DACL|SECINFO_OWNER| SECINFO_GROUP|SECINFO_SACL)) { /* Don't return SECINFO_LABEL if anything else was -- 2.5.0 From 8bdbe1c90c98efbd08fc70d773d236c4ba00b1ae Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 10:52:50 -0800 Subject: [PATCH 3/8] CVE-2015-7560: s3: smbd: Refuse to set an ACL from a POSIX file handle on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/nttrans.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/source3/smbd/nttrans.c b/source3/smbd/nttrans.c index 7255600..d2102ca 100644 --- a/source3/smbd/nttrans.c +++ b/source3/smbd/nttrans.c @@ -877,6 +877,12 @@ NTSTATUS set_sd(files_struct *fsp, struct security_descriptor *psd, return NT_STATUS_OK; } + if (S_ISLNK(fsp->fsp_name->st.st_ex_mode)) { + DEBUG(10, ("ACL set on symlink %s denied.\n", + fsp_str_dbg(fsp))); + return NT_STATUS_ACCESS_DENIED; + } + if (psd->owner_sid == NULL) { security_info_sent &= ~SECINFO_OWNER; } -- 2.5.0 From 612b032e2dedd3e07bbe79718ecbb3b68ffbb7a5 Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:22:12 -0800 Subject: [PATCH 4/8] CVE-2015-7560: s3: smbd: Refuse to set a POSIX ACL on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 7f47579..2f01e87 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -6480,6 +6480,7 @@ static NTSTATUS smb_set_posix_acl(connection_struct *conn, uint16 num_def_acls; bool valid_file_acls = True; bool valid_def_acls = True; + NTSTATUS status; if (total_data < SMB_POSIX_ACL_HEADER_SIZE) { return NT_STATUS_INVALID_PARAMETER; @@ -6507,6 +6508,11 @@ static NTSTATUS smb_set_posix_acl(connection_struct *conn, return NT_STATUS_INVALID_PARAMETER; } + status = refuse_symlink(conn, fsp, smb_fname->base_name); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + DEBUG(10,("smb_set_posix_acl: file %s num_file_acls = %u, num_def_acls = %u\n", smb_fname ? smb_fname_str_dbg(smb_fname) : fsp_str_dbg(fsp), (unsigned int)num_file_acls, -- 2.5.0 From 28e6120d14e5a942df386db0444abaa93a764207 Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:24:36 -0800 Subject: [PATCH 5/8] CVE-2015-7560: s3: smbd: Refuse to get a POSIX ACL on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 2f01e87..3a098d1 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -4959,6 +4959,13 @@ NTSTATUS smbd_do_qfilepathinfo(connection_struct *conn, uint16 num_file_acls = 0; uint16 num_def_acls = 0; + status = refuse_symlink(conn, + fsp, + smb_fname->base_name); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + if (fsp && fsp->fh->fd != -1) { file_acl = SMB_VFS_SYS_ACL_GET_FD(fsp); } else { -- 2.5.0 From 659bdb80aa65c02cf4f44377cc3bcffb2a817ee0 Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:05:48 -0800 Subject: [PATCH 6/8] CVE-2015-7560: s3: smbd: Set return values early, allows removal of code duplication. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 3a098d1..6fdd1da 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -210,11 +210,12 @@ NTSTATUS get_ea_names_from_file(TALLOC_CTX *mem_ctx, connection_struct *conn, size_t num_names; ssize_t sizeret = -1; + if (pnames) { + *pnames = NULL; + } + *pnum_names = 0; + if (!lp_ea_support(SNUM(conn))) { - if (pnames) { - *pnames = NULL; - } - *pnum_names = 0; return NT_STATUS_OK; } @@ -264,10 +265,6 @@ NTSTATUS get_ea_names_from_file(TALLOC_CTX *mem_ctx, connection_struct *conn, if (sizeret == 0) { TALLOC_FREE(names); - if (pnames) { - *pnames = NULL; - } - *pnum_names = 0; return NT_STATUS_OK; } -- 2.5.0 From 4ba5e7cf01b8074b0313ecb7e218355d771df1cc Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:29:38 -0800 Subject: [PATCH 7/8] CVE-2015-7560: s3: smbd: Silently return no EA's available on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 6fdd1da..8b6e4b2 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -209,6 +209,7 @@ NTSTATUS get_ea_names_from_file(TALLOC_CTX *mem_ctx, connection_struct *conn, char **names, **tmp; size_t num_names; ssize_t sizeret = -1; + NTSTATUS status; if (pnames) { *pnames = NULL; @@ -219,6 +220,14 @@ NTSTATUS get_ea_names_from_file(TALLOC_CTX *mem_ctx, connection_struct *conn, return NT_STATUS_OK; } + status = refuse_symlink(conn, fsp, fname); + if (!NT_STATUS_IS_OK(status)) { + /* + * Just return no EA's on a symlink. + */ + return NT_STATUS_OK; + } + /* * TALLOC the result early to get the talloc hierarchy right. */ -- 2.5.0 From 9d8c7274ab87a0c07367e872ca1db7fd72886fde Mon Sep 17 00:00:00 2001 From: Jeremy Allison Date: Tue, 5 Jan 2016 11:33:48 -0800 Subject: [PATCH 8/8] CVE-2015-7560: s3: smbd: Refuse to set EA's on a symlink. BUG: https://bugzilla.samba.org/show_bug.cgi?id=11648 Signed-off-by: Jeremy Allison Reviewed-by: Michael Adam --- source3/smbd/trans2.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/source3/smbd/trans2.c b/source3/smbd/trans2.c index 8b6e4b2..98fd2af 100644 --- a/source3/smbd/trans2.c +++ b/source3/smbd/trans2.c @@ -584,6 +584,7 @@ NTSTATUS set_ea(connection_struct *conn, files_struct *fsp, const struct smb_filename *smb_fname, struct ea_list *ea_list) { char *fname = NULL; + NTSTATUS status; if (!lp_ea_support(SNUM(conn))) { return NT_STATUS_EAS_NOT_SUPPORTED; @@ -593,6 +594,12 @@ NTSTATUS set_ea(connection_struct *conn, files_struct *fsp, return NT_STATUS_ACCESS_DENIED; } + status = refuse_symlink(conn, fsp, smb_fname->base_name); + if (!NT_STATUS_IS_OK(status)) { + return status; + } + + /* For now setting EAs on streams isn't supported. */ fname = smb_fname->base_name; -- 2.5.0